ΔE 18.7, loose: different enough that you should pick on purpose. Green Gold is a little darker, warmer than Warp Lightning. They are different kinds of paint: Citadel Warp Lightning is a one-coat contrast-style paint and Golden Green Gold is an opaque base/layer paint, so they won’t behave the same on the model even where the colour is close.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 19). Green Gold is a little darker, warmer than Warp Lightning. They are different kinds of paint.
The same difference applies the other way round: Warp Lightning is a little lighter, cooler.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Warp Lightning on the colour wheel See Green Gold on the colour wheel
All matches: Warp Lightning equivalents · Green Gold equivalents