Preheat oven to 350 degrees.
Lightly coat a baking dish with olive oil. In a small bowl, combine next 5 ingredients (oregano through onion); blend well then spread mixture evenly on the center of one side of each chicken breast half; fold the other side over the top; place in prepared baking dish. Sprinkle with salt and pepper then pour the tomato sauce on top.
Cover baking dish with foil and bake for 30 to 45 minutes or until chicken juices run clear. Serve and enjoy!