Chocolate liquor is a viscous liquid obtained by the grinding of cocoa nibs from the cocoa bean*. It is used in making candy, drinks and other chocolate-flavored products. It does not contain any alcohol, so it is not haram.
And ALLAH, Subhanahu wa ta’ala, knows best.
*Source: Halal Food Production, Mian N. Riaz & Muhammad M. Chaudry, CRC Press