ΔE 10.8, fair: the same colour family, but not a straight swap. Sand Yellow RLM79 is a little lighter, cooler than NATO Brown.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). Sand Yellow RLM79 is a little lighter, cooler than NATO Brown.
The same difference applies the other way round: NATO Brown is a little darker, 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 NATO Brown on the colour wheel See Sand Yellow RLM79 on the colour wheel
All matches: NATO Brown equivalents · Sand Yellow RLM79 equivalents