Preheat your oven to 375°F (190°C).
In a bowl, mix together the mayo, Parmesan, garlic powder, onion powder, salt, and pepper.
Place the chicken breasts in a baking dish.
Spread the mayo mixture evenly over the top of each piece of chicken.
Bake uncovered for 25–30 minutes, or until the chicken reaches an internal temperature of 165°F (74°C) and the top is golden.
Let it rest a few minutes before serving. Sprinkle with chopped parsley if you're feeling fancy.