ΔE 14.3, fair: the same colour family, but not a straight swap. Waaagh! Flesh is noticeably darker, more saturated than IJA Nakajima Green.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 14). Waaagh! Flesh is noticeably darker, more saturated than IJA Nakajima Green.
The same difference applies the other way round: IJA Nakajima Green is noticeably lighter, more muted.
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 IJA Nakajima Green on the colour wheel See Waaagh! Flesh on the colour wheel
All matches: IJA Nakajima Green equivalents · Waaagh! Flesh equivalents