Preheat your oven to 425 degrees.
Place chicken breasts in a baking dish and drizzle with olive oil. Season chicken with oregano, basil, salt, pepper and half of the garlic divided between each chicken breast. Rub seasoning all over each breast.
Arrange tomatoes around the chicken in the dish.
Whisk together balsamic vinegar, brown sugar and remaining garlic to combine. Pour over the chicken breasts, flip each breast in the sauce to evenly coat.
Bake in your preheated oven for 35 minutes
Remove from the oven at the 35 minute mark and change oven heat to broil. Top each chicken breast with mozzarella cheese.
Bake for another 3-5 minutes on broil, or until the cheese is melted and golden.
After baking, allow your chicken to rest for 5 minutes before cutting into it.