Preheat oven to 425°F (220°C). Line a baking sheet with foil and lightly grease it.
In a small bowl, combine mayonnaise and Parmesan cheese.
In another bowl, mix breadcrumbs, garlic powder, and black pepper.
Spread the mayo mixture over the top of each chicken breast.
Sprinkle the breadcrumb mixture evenly over the coated chicken.
Place chicken on prepared baking sheet and lightly spray the tops with cooking spray.
Bake for 20–25 minutes, or until chicken reaches an internal temperature of 165°F.
Let rest for 5 minutes before serving.