The term is also often used to explain something that falls into a person's area of expertise.
Child 1: "How can we get this hot girl to take her clothes off?"
Child 2: "Ask Hugh Heffner, that's right in his wheelhouse."
I'm guessing it originates from the fact that a wheelhouse is the room on the bridge of a ship where you steer from, providing you with clear view & control to steer the situation.
Singing this song in that key is right in your wheelhouse.
That pitch was thrown down & out, right in the batter's wheelhouse.