Pour oil into a large skillet and heat over medium-high heat. Add the garlic and cook for 1 minute. Add the chicken and cook, about 4 minutes per side, or until cooked through and the juices run clear. Take out the chicken and set aside. Reduce the heat to medium and add the balsamic vinegar and chicken broth to the pan. Stir and scrape the bottom of the pan to remove any browned bits. Add the tomatoes, bring to a boil and cook for 3 to 5 minutes. Serve over chicken.
