ΔE 17.4, loose: different enough that you should pick on purpose. IJN Gray Green Nakajima is noticeably darker, more muted, warmer than Aquamarine.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 17). IJN Gray Green Nakajima is noticeably darker, more muted, warmer than Aquamarine.
The same difference applies the other way round: Aquamarine is noticeably lighter, more saturated, 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 Aquamarine on the colour wheel See IJN Gray Green Nakajima on the colour wheel
All matches: Aquamarine equivalents · IJN Gray Green Nakajima equivalents