ΔE 55.6, loose: different enough that you should pick on purpose. Fallen Grass is noticeably darker, much more muted, cooler than Snake Scales.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 56). Fallen Grass is noticeably darker, much more muted, cooler than Snake Scales.
The same difference applies the other way round: Snake Scales is noticeably lighter, 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.
See Snake Scales on the colour wheel See Fallen Grass on the colour wheel
All matches: Snake Scales equivalents · Fallen Grass equivalents