ΔE 9.3, close: similar, with a visible difference side by side. Nurgling Green is a little lighter, cooler than Greatcoat Green.
Usually, if you are not matching paint already on the model. Close match (ΔE 9). Nurgling Green is a little lighter, cooler than Greatcoat Green.
The same difference applies the other way round: Greatcoat Green is a little darker, warmer.
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 Greatcoat Green on the colour wheel See Nurgling Green on the colour wheel
All matches: Greatcoat Green equivalents · Nurgling Green equivalents