In a sealable bag, add the chicken, balsamic vinaigrette, and italian seasoning. Let the chicken marinate in the fridge for at least 10 minutes or up to overnight.

Heat oil in a grill pan or skillet over medium heat. Remove the chicken from the marinade (discarding extra marinade) and place it in the pan. Cook about 5-10 minutes on each side (depending on thickness) until the center is no longer pink. Serve.