ΔE 11.9, fair: the same colour family, but not a straight swap. Khaki Grey is a little darker, cooler than Walnut.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 12). Khaki Grey is a little darker, cooler than Walnut.
The same difference applies the other way round: Walnut is a little lighter, 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 Walnut on the colour wheel See Khaki Grey on the colour wheel
All matches: Walnut equivalents · Khaki Grey equivalents