Chocolate (Chipping) vs Hardened Carapace

How close are they?

ΔE 9.2, close: similar, with a visible difference side by side. Hardened Carapace is a little lighter, more muted than Chocolate (Chipping).

Can I use Hardened Carapace instead of Chocolate (Chipping)?

Usually, if you are not matching paint already on the model. Close match (ΔE 9). Hardened Carapace is a little lighter, more muted than Chocolate (Chipping).

Can I use Chocolate (Chipping) instead of Hardened Carapace?

The same difference applies the other way round: Chocolate (Chipping) is a little darker, more saturated.

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.