Preheat your oven to 375°F (190°C). Lightly grease a 9x13 inch baking dish with cooking spray.

In a medium bowl, mix together the mayonnaise, Parmesan cheese, garlic powder, seasoned salt, and black pepper until well combined.

Lay the chicken breasts into the prepared baking dish in a single layer. If the breasts are very thick, you may pound them slightly for even cooking.

Spread the mayonnaise mixture generously and evenly over the top of each chicken breast.

Bake for 45 minutes, or until the chicken reaches an internal temperature of 165°F (74°C) and the topping is golden brown.

Remove from the oven and let the chicken rest for 5 minutes before serving to retain the juices.