Preheat oven to 400°F and line a baking sheet with parchment paper.

Using a sharp knife, carefully butterfly each chicken breast by cutting horizontally through the middle, leaving one edge intact so it opens like a book.

Season the inside and outside of each chicken breast with garlic powder, salt, and pepper.

Layer mozzarella slices, tomato slices, and basil leaves inside each chicken breast, then fold closed and secure with toothpicks if needed.

Heat olive oil in an oven-safe skillet over medium-high heat and sear chicken for 2-3 minutes per side until golden.

Transfer skillet to oven and bake for 12-15 minutes until chicken reaches 165°F internal temperature.

Remove from oven, drizzle with balsamic glaze, and let rest for 5 minutes before serving.