ΔE 10.9, fair: the same colour family, but not a straight swap. Thar Brown is a little lighter, more saturated, cooler than Gnome Cheeks.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). Thar Brown is a little lighter, more saturated, cooler than Gnome Cheeks.
The same difference applies the other way round: Gnome Cheeks is a little darker, more muted, 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 Gnome Cheeks on the colour wheel See Thar Brown on the colour wheel
All matches: Gnome Cheeks equivalents · Thar Brown equivalents