Preheat the oven to 375 degrees F. Line a baking sheet with parchment paper or nonstick aluminum foil and spray with cooking spray.
Season each chicken breast with salt and pepper, then coat each breast with cooking spray. In a shallow bowl, mix the breadcrumbs and Parmesan. Press the chicken breasts into the mixture 1 at a time to coat on all sides, shaking off the excess. Transfer to the prepared baking sheet. Bake, flipping halfway through, until the juices run clear, 20 to 25 minutes.
Remove the chicken from the oven and turn on the broiler. Spoon the pizza sauce evenly over the top of each chicken breast and top with a slice of mozzarella. Place under the broiler and watch for the cheese to melt and bubble. Serve.