ΔE 14.9, fair: the same colour family, but not a straight swap. Chestnut Brown is a little lighter, cooler than Wyldwood. They are different kinds of paint: Citadel Wyldwood is a one-coat contrast-style paint and Nocturna Models Chestnut Brown is an opaque base/layer paint, so they won’t behave the same on the model even where the colour is close.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 15). Chestnut Brown is a little lighter, cooler than Wyldwood. They are different kinds of paint.
The same difference applies the other way round: Wyldwood 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 Wyldwood on the colour wheel See Chestnut Brown on the colour wheel
All matches: Wyldwood equivalents · Chestnut Brown equivalents