ΔE 14.7, fair: the same colour family, but not a straight swap. IJN Gray Green Nakajima is a little lighter, more muted, cooler than Potion Green.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 15). IJN Gray Green Nakajima is a little lighter, more muted, cooler than Potion Green.
The same difference applies the other way round: Potion Green is a little darker, more saturated, 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 Potion Green on the colour wheel See IJN Gray Green Nakajima on the colour wheel
All matches: Potion Green equivalents · IJN Gray Green Nakajima equivalents