ΔE 25.8, loose: different enough that you should pick on purpose. Zombie Skin is noticeably lighter, warmer than Militarum Green.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 26). Zombie Skin is noticeably lighter, warmer than Militarum Green.
The same difference applies the other way round: Militarum Green is noticeably darker, 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 Militarum Green on the colour wheel See Zombie Skin on the colour wheel
All matches: Militarum Green equivalents · Zombie Skin equivalents