ΔE 14.4, fair: the same colour family, but not a straight swap. Nuclear Yellow is a little lighter, more saturated than Hardened Leather.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 14). Nuclear Yellow is a little lighter, more saturated than Hardened Leather.
The same difference applies the other way round: Hardened Leather is a little darker, 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 Hardened Leather on the colour wheel See Nuclear Yellow on the colour wheel
All matches: Hardened Leather equivalents · Nuclear Yellow equivalents