Preheat your grill to medium-high heat.
Pat the chicken breasts dry with paper towels and season both sides with salt, pepper, and garlic powder.
Drizzle olive oil over the chicken and rub it in to coat evenly.
Place the chicken on the grill and cook for about 6-7 minutes on each side, or until the internal temperature reaches 165°F.
During the last few minutes of grilling, place slices of mozzarella cheese on top of the chicken and close the grill lid to melt the cheese.
Once the chicken is cooked and the cheese is melted, remove it from the grill and let it rest for 5 minutes.
Top each chicken breast with tomato slices, fresh basil leaves, and a drizzle of balsamic glaze before serving.