Nomad Flesh vs Mars Orange

How close are they?

ΔE 15.7, loose: different enough that you should pick on purpose. Mars Orange is a little darker, more saturated, warmer than Nomad Flesh.

Can I use Mars Orange instead of Nomad Flesh?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Mars Orange is a little darker, more saturated, warmer than Nomad Flesh.

Can I use Nomad Flesh instead of Mars Orange?

The same difference applies the other way round: Nomad Flesh is a little lighter, more muted, 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.