ΔE 13.8, fair: the same colour family, but not a straight swap. Dark Flesh is a little darker, more muted, warmer than Nickel Azo Yellow.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 14). Dark Flesh is a little darker, more muted, warmer than Nickel Azo Yellow.
The same difference applies the other way round: Nickel Azo Yellow is a little 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 Nickel Azo Yellow on the colour wheel See Dark Flesh on the colour wheel
All matches: Nickel Azo Yellow equivalents · Dark Flesh equivalents