Season both sides of chicken breasts with salt and pepper.
Heat olive oil in a large skillet over medium heat; cook seasoned chicken breasts until chicken is browned, 3 to 4 minutes per side. Add onion and garlic, cook and stir until onion is browned, 3 to 4 minutes.
In a medium bowl mix the tomatoes, balsamic vinegar, basil, oregano and thyme.
Spoon the tomato mixture over the chicken
Simmer until chicken is no longer pink and the juices run clear, about 15 minutes.