Mix coleslaw mix with dressing, 1 cup Cheddar-Monterey Jack cheese blend, salt, and black pepper in a bowl; transfer to 2-quart baking dish. Mix butter, bread crumbs, and 1/4 cup Cheddar-Monterey Jack cheese blend together in a separate bowl until well combined; spread crumb mixture over coleslaw mixture.
Bake in the preheated oven until the coleslaw is golden brown and edges are bubbling, 15 to 20 minutes. Let stand 5 minutes before serving.