ΔE 23.9, loose: different enough that you should pick on purpose. Nuclear Yellow is noticeably darker, more muted, warmer than Imperial Fist.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 24). Nuclear Yellow is noticeably darker, more muted, warmer than Imperial Fist.
The same difference applies the other way round: Imperial Fist 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 Imperial Fist on the colour wheel See Nuclear Yellow on the colour wheel
All matches: Imperial Fist equivalents · Nuclear Yellow equivalents