Whisk 1/4 cup vinegar, oil, salt and pepper in a large bowl. Add tomatoes, onion and basil, stir to combine. Cover and allow to marinate for an hour.
Marinate chicken olive oil, balsamic vinegar, garlic, dried basil, salt, and pepper. Marinate chicken in marinade for 30 minutes to an hour or overnight preferably.
In a skillet over medium high heat, cook chicken breast for about 8 minutes one one side without flipping (5 minutes for thin-cut breasts). Flip the chicken, and cook on the second side until well browned and cooked through (internal temperature should reach 165ºF).
Remove chicken from skillet, allow to rest for 5 minutes before cutting.
Add cooked cut chicken and diced bell pepper into the bowl with tomatoes, mix and serve alone or as a side. Enjoy!
