Nuclear Sunrise vs Shadow Flesh

How close are they?

ΔE 40.8, loose: different enough that you should pick on purpose. Shadow Flesh is a little lighter, much more muted, cooler than Nuclear Sunrise.

Can I use Shadow Flesh instead of Nuclear Sunrise?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 41). Shadow Flesh is a little lighter, much more muted, cooler than Nuclear Sunrise.

Can I use Nuclear Sunrise instead of Shadow Flesh?

The same difference applies the other way round: Nuclear Sunrise is a little darker, much 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.