ΔE 8.3, close: similar, with a visible difference side by side. Walnut Brown is more muted, warmer than Mid Battle Dress. They are different kinds of paint: Army Painter Mid Battle Dress is an opaque base/layer paint and Green Stuff World Walnut Brown is an ink, glaze or transparent paint, so they won’t behave the same on the model even where the colour is close.
Usually, if you are not matching paint already on the model. Close match (ΔE 8). Walnut Brown is more muted, warmer than Mid Battle Dress. They are different kinds of paint.
The same difference applies the other way round: Mid Battle Dress is 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 Mid Battle Dress on the colour wheel See Walnut Brown on the colour wheel
All matches: Mid Battle Dress equivalents · Walnut Brown equivalents