Preheat oven to 375°. In a bowl, combine ricotta, ½ cup mozzarella, ¼ cup parmesan, egg and basil. Season with pepper and salt.
Cut a pocket in chicken-breast. Stuff each with 2 tbsp marinara-sauce & ¼ of ricotta mix.
Arrange stuffed-chicken at the bottom of a 9x13" baking-dish. Season with pepper and salt. Sprinkle with Italian-seasoning & drizzle with oil.
Bake until chicken is nearly cooked through, reaching an internal temperature of 155°, about 25minutes or 35minutes for bigger breasts. Discard excess juices at the pan.
Change oven to broil & top chicken with remaining 1 cup marinara, ¾ cup mozzarella & 2 tbsp parmesan. Broil till cheese is golden & bubbly and chicken-reaches an internal temperature of 165° for 4-5minutes or longer.
Garnish with more basil before serving for more taste.