Chocolate rooster with chocolate hen should give just chocolate chicks.
Solid rooster with a hen split to mottling, should mean that no chicks show mottling but about half of them carry the mottling gene.
So about half of chicks will be chocolate with no mottling gene, and the other half will be chocolate and carry the mottling gene (split to mottled.)
The chocolate is no surprise, but I would not expect any chick to show mottling unless both parents have the mottling gene. So if each parent carries mottling, the chick could inherit it from both of them, and then the chick could show mottling.
Given that the chick just hatched, I think it will take quite a while to be completely sure, but it might have down that looks like the down of a mottled chick, without actually showing mottling in the feathers when it matures. Chick down can be confusing, and I don't know all that much about what affects it.
Maybe you can take pictures of the chick now, then at intervals as it grows. That will not help predict what color THIS chick is, but might help you and other people learn more, to make more accurate predictions in the future. (Besides, I like to look at pictures of chickens. So I'd encourage pictures even if the only reason was "so I can see the cute chick.")
