ΔE 11.4, fair: the same colour family, but not a straight swap. Gorgon Brown is a little lighter, more muted, cooler than Burnt Sienna.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). Gorgon Brown is a little lighter, more muted, cooler than Burnt Sienna.
The same difference applies the other way round: Burnt Sienna is a little darker, more saturated, 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 Burnt Sienna on the colour wheel See Gorgon Brown on the colour wheel
All matches: Burnt Sienna equivalents · Gorgon Brown equivalents