ΔE 7.9, close: similar, with a visible difference side by side. Burnt Umber is more muted, warmer than NATO Brown.
Usually, if you are not matching paint already on the model. Close match (ΔE 8). Burnt Umber is more muted, warmer than NATO Brown.
The same difference applies the other way round: NATO Brown 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 NATO Brown on the colour wheel See Burnt Umber on the colour wheel
All matches: NATO Brown equivalents · Burnt Umber equivalents