The decision was taken under pressure from France, which sources more than 70% of electricity from nuclear power plants, as well as gas-dependent eastern and southern EU members.
The European Commission's draft taxonomy text, seen by the newspaper, suggests awarding the green label to nuclear power as long as safe disposal of toxic waste is guaranteed. Only power plants built until 2045 will be considered as green.
Natural gas will be deemed a "transitional" energy source on condition that it eventually replaces a transitional fossil fuel and carbon emissions from using it are capped at 270 grams per kilowatt.
The new taxonomy was proposed in a bid to end the so-called greenwashing of new energy projects in the industry as the EU seeks to cut greenhouse gas emissions to net zero by 2050.