Bieniemy has called the plays in KC for the last two seasons.
Reid is the primary play-caller, as he was when Pederson and Nagy were there. Towards the end of Nagy’s run he ceded play-calling duty to him, maybe he’s done the same with Bieniemy (in fact I wouldn’t be surprised if Bieniemy called the shots in yesterday’s game.)
It’s the Reid and Mahomes show over there, for obvious reasons.