Nix repeatedly tried to claim he could not answer certain questions because an inquiry had been launched by the Information Commissioner's Office but the chairman of the Digital, Culture, Media and Sport Select Committee, Conservative MP Damian Collins, pointed out the ICO had told him they saw no reason why Nix could not answer their questions.
Nix then accused the information watchdog of "abusing his parliamentary privilege" by using comments he made to the committee on February 27 as a basis for a search warrant on his firm's offices.
Cambridge Analytica reportedly acquired and used data from 87 million Facebook profiles in political campaigns, particularly in the 2016 US election and the 2016 Brexit referendum in the UK.
Last month the firm, which had worked for Donald Trump campaign, entered Chapter 7 bankruptcy protection in the US and went into administration in the UK after the board decided it could no longer be a "viable going concern" because of a "media storm" of negative publicity.
Cambridge Analytica became the center of a data-sharing row after it emerged the firm had acquired data from Global Science Research (GSR), which in turn had collected millions of Facebook users' personal details, in breach of the social network's rules.
The damage to the firm's reputation was compounded when Nix and Mark Turnbull, managing director of sister company SCL Elections, were caught on camera telling an undercover reporter from Channel 4 News how they were capable of manipulating elections and even used "honey trap" women to entrap politicians in sex scandals.
'Victim' of 'Global Liberal Media' Attack
Later he was asked by SNP MP Brendan O'Hara whether he felt he was in fact "the victim."
"What happened if I was the victim? Let's just run with this hypothesis for the moment? What if I was the victim? We were accused of working on Brexit, we didn't work on Brexit. We were accused of disseminating videos in Kenya. We didn't disseminate videos in Kenya. We were accused by Mr. Wylie of 'capturing governments, colonising countries and being part of some white, right-wing conspiracy'. What happens if none of that is actually true…and people realize that we were simply the guys who were perceived to have contributed to the Trump campaign and were wrongly accredited with being the architects of Brexit and as a result of the polarizing nature of those two political campaigns the global liberal media took umbrage and decided to put us in their crosshairs and decided to launch an extremely well co-ordinated and effective attack on us as a company in order to destroy our reputation and our business and all of this was underpinned by a stream of unfounded, groundless allegations by Mr. Wylie which gave the media the ammunition they needed and wanted to attack us for something, on Brexit, that we simply didn't do," Nix replied.
In April Mr. Collins asked Nix to return to the committee to clarify "inconsistencies" in his evidence but Nix had refused, citing the investigation by the information commissioner into the firm's use of data.
When he did appear on Wednesday, June 6, the encounter began with an immediate clash with Mr. Collins, who refused to allow Nix to make an opening statement.
Nix began to make the statement, in which he denied he had refused to return to testify, but was interrupted by Mr. Collins and then "insisted" he be allowed to finish the statement.
"It's not your place to insist. You are here to answer questions," replied Mr. Collins.
When the questioning began Nix was asked to explain why he had told the committee on February 27 that GSR's Facebook data had proved "fruitless" and had not been used.
'Genuine Misunderstanding'
Nix said it had been a "genuine misunderstanding" and he had thought the chairman was asking him if his company still possessed the data from GSR.
Mr. Collins said there had been "no ambiguity" in his questions and he did not accept that Nix could have misunderstood them.
He was asked by Labour MP Jo Stevens if he felt "embarrassed" by the revelations made by Channel 4.
Nix said he was extremely embarrassed for the damage he had caused to his company but he claimed the footage of him and Mr. Turnbull had been "heavily edited."
"In our over-zealousness to secure a contract Mr. Turnbull and I were guilty of hyperbole. We were just telling the client what we thought he wanted to hear," Nix said.
Ms. Stevens asked him if his company had any business ethics at all.
"Cambridge Analytica is staffed by very young and very ideological individuals who come from a broad range of ideologies and interests and have been working to see how data can be used to make the world a better place," Nix said.
Mr. Collins asked him about a specific passage in the footage where Nix referred to using "beautiful Ukrainian girls" to entrap politicians and said "I find that works very well."
'That Was Just A Lie'
"Was that just a lie?" asked Mr. Collins.
"That was just a lie to impress the people," replied Nix, who denies the company had ever practised such "dark arts".
He was then asked about a sex scandal in Kenya, which damaged the reputation of a politician running against a Cambridge Analytica-backed campaign.
"Let me make it categorical. There is no truth to it. We have never done anything which involved a honey trap or a sex scandal for political leverage. I can't be more blunt than that," said Nix.
Nix said he had been "foolish" to "fall for a trick" and claimed the undercover reporter had deliberately led him down a line of questioning and deceived him.
Facebook suspended the accounts of Cambridge Analytica in March as it emerged that a third-party application had transferred users' information to them, which is forbidden by the social network's rules.
The information then may have been used for political campaigning.
Nix was suspended in March after a Channel 4 reporter secretly filmed him exposing some of the company's questionable practices.
Christian Matheson, a Labour MP, asked Nix if he felt he had just been "unlucky".
"I don't know that I was unlucky…I was fed questions to solicit certain answers. People would like to believe that we are a large, nefarious multi-national company that influences politics and other things around the world. But we are a very small advertising company which worked on one campaign (the Trump campaign) which was 25 percent of our business and most of our time is spent selling toothpaste and automotives," said Nix.
Nix claimed the main instigator of the campaign of negative publicity against Cambridge Analytica and SCL Elections had been Christopher Wylie, who had worked for the company but became "resentful" and he claimed Wylie tried to set up his own company, doing very similar work, and was pitching to exactly the same Republican politicians that Cambridge Analytica worked for.
"He was agnostic about where the money came from and was happy to talk to Russians. In fact he even told me he found the idea of working for crazy, evil Russians quite intriguing," Nix said.
Nix Says Financial Times Allegations 'False'
The Financial Times claimed on Wednesday, June 6, that Nix withdrew US$8 million from Cambridge Analytica before it collapsed.
Nix was asked about the article by Mr. Collins.
"I saw that today. The allegation which is made in the article is false. The facts are not correct, other than that I can't speak to it. What I can say is that over the last three months since the media storm has erupted I have invested millions of my own money in to meet staff salaries, bonuses and redundancies," Nix told replied.
He was also asked about a report in The Guardian newspaper that one of his top executives at Cambridge Analytica, Brittany Kaiser, had visited Julian Assange in the Ecuadorean embassy in London in a bid to gain access to damaging emails.
Nix said it was the first he had of it and she had certainly not discussed it with him, nor was she going as a representative of Cambridge Analytica.
Nix is not the only reluctant witness to the fake news inquiry.
On Tuesday, June 5, Mr Collins wrote to the Speaker of the House of Commons asking for a debate in the House and seeking an order compelling Dominic Cummings, the campaign director of Vote Leave, to attend the select committee.
"We need Dominic Cummings to appear before our committee as a witness, so that he can clarify allegations raised with this committee about the unlawful coordination of EU referendum campaigns, campaign spending, and misuse of people's personal data. As the email correspondence attached to the report shows, we have made repeated, reasonable requests for him to appear, so far he has refused to do this," said Mr. Collins in a statement on the committee's website.