Answer:
Object complement
Step-by-step explanation:
An object complement is a noun, a pronoun, or an adjective that is placed right after a direct object and that renames, identifies or states what that direct object has become. It is often used with verbs like appoint, call, elect, choose, name, make, create.
In the sentence, the boss is the subject (He or she is the one that performs the action), Ms. Brandy is the direct object (She receives the action "appointed") and chairwoman is an object complement because it states what the direct object became: Ms. Brandy is now a chairwoman.