Place your chicken breasts into a ziploc bag, and pound them to about 1/4-1/2 inch thick using a meat tenderizer. Alternately, you can slice then in half lengthwise, making thin cutlets.
Warm a large skillet over medium high heat. Add the olive oil and heat until warm. Add the chicken in a single layer and sprinkle with half of the salt, pepper, and Italian seasoning. Cook without touching for about two minutes, you'll notice the edges of the chicken cooking, while only the center is pink. Flip the chicken over and sprinkle with the remaining salt, pepper, and Italian seasoning. Top each piece of chicken with cheese and then tomato slices. Cover with a lid and cook an additional 3-4 minutes.
Check the chicken for doneness. I use this meat thermometer, and the temperature should read 165°F.
Sprinkle with fresh basil and drizzle with the balsamic vinegar right before serving. ENJOY!
Notes
Cutlets - If you prefer, you can also cut the chicken breasts in half lengthwise to form cutlets, and skip the tenderizing step altogether.
How to tell when chicken is done: I highly recommend investing in a meat thermometer to help you know when your meats like chicken and pork are fully cooked. In the even you don't have one, you can check the chicken for doneness by piercing the center with a knife and fork. The juices will run clear when the chicken is fully cooked. If they are pink, the chicken needs more time.