ΔE 9.1, close: similar, with a visible difference side by side. Nurgling Green is a little lighter, cooler than Witch Brew.
Usually, if you are not matching paint already on the model. Close match (ΔE 9). Nurgling Green is a little lighter, cooler than Witch Brew.
The same difference applies the other way round: Witch Brew 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 Witch Brew on the colour wheel See Nurgling Green on the colour wheel
All matches: Witch Brew equivalents · Nurgling Green equivalents