ΔE 10.6, fair: the same colour family, but not a straight swap. US Earth Red is a little darker, more muted than Walnut.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). US Earth Red is a little darker, more muted than Walnut.
The same difference applies the other way round: Walnut is a little lighter, more saturated.
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 US Earth Red on the colour wheel
All matches: Walnut equivalents · US Earth Red equivalents