Preheat oven to 375. Lightly spray a 9x13 baking dish with nonstick spray and set aside
In a medium bowl, mix together the sour cream, garlic powder, seasoned salt, pepper and 3 oz parmesan cheese
Place the chicken breasts evenly in the pan. Spread the sour cream mixture on top of the chicken. Sprinkle with remaining parmesan cheese.
Bake for 25-30 minutes or until the chicken is cooked through.
Turn the oven to broil and place the pan under the broiler for 2-3 minutes until lightly browned on top.
Serve immediately.