Preheat your oven to 400 degrees
With a sharp knife, butterfly the chicken breasts then put them on a cookie sheet already lined with tin foil.
Generously season both sides of the chicken breasts with salt, pepper, and dried oregano. I added a small sprinkling of dried basil and parsley to the inside of the butterflied chicken too.
Wash your hands, then take the mozzarella sticks out from their packaging. Pull the mozzarella sticks in half, and place them side by side, covering one half of the inside of the chicken. Fold the chicken in half, enclosing the mozzarella sticks inside.
Set aside and wash your hands again.
Place the sliced tomatoes on a plate. Give them a small pinch of salt and dried basil on one side. Lay 3-4 slices of tomato over the raw chicken, covering the entire surface.
Put the chicken breasts into the oven and cook for 20 minutes, or until the chicken reaches an internal temperature of 165 degrees.
Pull the chicken from the oven and let rest for 5 minutes, so the juice has time to redistribute throughout the chicken. Feel free to tent the resting chicken with tin foil to keep it warm.
Put the chicken on a plate, top with the fresh basil, and serve with your favorite vegetable. I just did a side salad of arugula, baby spinach, a small amount of red onion, and balsamic dressing.