Preheat the oven to 400°F (200°C).
Spray a baking dish with cooking spray.
In a shallow bowl, beat the egg. In another bowl, mix breadcrumbs, 3 tablespoons Parmesan, oregano, basil, thyme, and garlic powder.
Coat the chicken breasts in the egg wash, then dredge them in the breadcrumb mixture.
Place the breaded chicken in the baking dish and bake for 20 minutes.
Remove from oven, spoon spaghetti sauce over each chicken breast, and sprinkle with mozzarella and remaining Parmesan.
Return to the oven and bake for an additional 5-7 minutes, or until cheese is melted and bubbly.
Serve hot and enjoy!