ΔE 19.4, loose: different enough that you should pick on purpose. Troll Snot Green is a little lighter, much more saturated, cooler than Necrotic Flesh.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 19). Troll Snot Green is a little lighter, much more saturated, cooler than Necrotic Flesh.
The same difference applies the other way round: Necrotic Flesh is a little darker, much more muted, 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 Necrotic Flesh on the colour wheel See Troll Snot Green on the colour wheel
All matches: Necrotic Flesh equivalents · Troll Snot Green equivalents