Lightly grease a 9x13" baking dish with non-stick cooking spray.
Arrange the chicken breasts evenly out in the prepared dish. Salt & pepper them.
In a small mixing bowl, whisk together the mayonnaise, Parmesan cheese, Italian seasoning, and garlic powder until evenly combined.
Add the mayo mixture in dollops evenly out over the chicken, then use a spatula to spread as necessary to cover the chicken completely.
Bake the chicken at 400° for 20-25 minutes, or until an a meat thermometer reads 165°. If the cheesy crust is browning too much before the meat's done, loosely tent with aluminum foil.
Remove the baking dish from the oven, and let the chicken rest for 5 minutes before serving.
