1. Cook rice according to package directions, omitting fat and salt.
2. In a large mixing bowl, combine cooked rice, turkey, Italian seasoning, onion, Parmesan, 1/4 cup tomatoes and 1 cup mozzarella. Fill peppers with rice mixture.
3. Coat the inside of a slow cooker with cooking spray and placed filled peppers upright in cooker. Spoon remaining tomatoes over and between peppers; top each pepper with 1/4 cup mozzarella. Cook on low 8 hours.