Preheat your oven to 375° and line a large baking sheet with a silicone baking mat or grease it.
Use a sharp knife to cut a pocket into the center of each chicken breast. Be careful not to cut all the way through.
Put equal amounts of tomato slices, mozzarella slices and basil leaves inside of each piece of chicken. Use toothpicks to close the pockets on the chicken as much as you can. Season each piece of chicken with the salt, pepper, garlic powder and Italian seasoning. Place on the prepared baking sheet.
Drizzle the olive oil over the chicken. Bake in the preheated oven for approximately 30 minutes, or until the chicken is cooked through. Top with the balsamic glaze.