Preheat the oven to 375°F. Spray 9- x 13-inch baking dish with cooking spray.
Cut chicken breasts in half lengthwise and transfer them to the baking dish.
Evenly season both sides of chicken with ½ teaspoon salt and ½ teaspoon of black pepper.
In a medium bowl, stir together mayonnaise, Parmesan cheese, remaining ½ teaspoon salt and ½ teaspoon pepper, onion powder, garlic powder, and paprika.
Spread the Parmesan mixture evenly on top of each piece of chicken.
Bake in the preheated oven for 25-30 minutes or until chicken reaches an internal temperature of 165°F. Remove from oven and garnish with parsley.
