Rinse and cut all visible fat off of chicken breasts. Coat a skillet with nonstick cooking spray (nonfat), and preheat over medium heat. Mince 2 of the garlic cloves, and place them in the skillet with the chicken breast in the skillet. Surround the chicken with the remaining garlic cloves.
Cook the chicken for 2-4 minutes on each side, or until the chicken and garlic cloves are browned. Remove the chicken from the skillet. Lay the onions, green peppers, and tomatoes over garlic cloves in baking pan (9-13-inch). Arrange the chicken over the tomatoes, onions, green peppers, and garlic. Pour wine and broth over chicken, and sprinkle with oregano and pepper. Cover and bake at 350 degrees F for 25-30 minutes. Serve chicken breasts with the vegetables and pan juices.