ΔE 9.9, close: similar, with a visible difference side by side. Nihilakh Oxide is more muted, warmer than Baby Blue. They are different kinds of paint: AMMO by Mig Baby Blue is an opaque base/layer paint and Citadel Nihilakh Oxide is a technical paint or medium, 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 10). Nihilakh Oxide is more muted, warmer than Baby Blue. They are different kinds of paint.
The same difference applies the other way round: Baby Blue 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 Baby Blue on the colour wheel See Nihilakh Oxide on the colour wheel
All matches: Baby Blue equivalents · Nihilakh Oxide equivalents