ΔE 8.0, close: similar, with a visible difference side by side. Nurgling Green is a little darker, warmer than Alga Green.
Usually, if you are not matching paint already on the model. Close match (ΔE 8). Nurgling Green is a little darker, warmer than Alga Green.
The same difference applies the other way round: Alga Green 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 Alga Green on the colour wheel See Nurgling Green on the colour wheel
All matches: Alga Green equivalents · Nurgling Green equivalents