ΔE 16.7, loose: different enough that you should pick on purpose. Muddy Olive is a little darker, much more muted, warmer than Greenskin.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 17). Muddy Olive is a little darker, much more muted, warmer than Greenskin.
The same difference applies the other way round: Greenskin is a little lighter, much 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 Greenskin on the colour wheel See Muddy Olive on the colour wheel
All matches: Greenskin equivalents · Muddy Olive equivalents