ΔE 22.8, loose: different enough that you should pick on purpose. Gnarls Green is noticeably darker, much more muted than Orruk Flesh.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 23). Gnarls Green is noticeably darker, much more muted than Orruk Flesh.
The same difference applies the other way round: Orruk Flesh is noticeably lighter, much more saturated.
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 Orruk Flesh on the colour wheel See Gnarls Green on the colour wheel
All matches: Orruk Flesh equivalents · Gnarls Green equivalents