In a bowl, add the diced tomatoes, basil leaves, grated garlic, extra virgin olive oil, red pepper flakes, salt, and pepper. Mix together and set aside.
Rub each chicken breast with olive oil followed by Italian seasoning, salt, pepper, and garlic powder.
Heat a large skillet over medium heat and add one tablespoon of olive oil. Cook the seasoned chicken breasts for about 5–7 minutes on each side until fully cooked. Squeeze half of a lemon over the chicken halfway through cooking.
Once the chicken is cooked through, reduce the heat slightly. Place two slices of mozzarella cheese on top of each breast and cover the skillet to melt the cheese.
Remove the skillet from heat once the mozzarella has melted. Top each chicken breast with basil pesto and the prepared tomato mixture. Drizzle balsamic glaze over everything and serve immediately.