In a small bowl, whisk together all the marinade ingredients until well-combined. Place your chicken breasts in a resealable plastic bag or shallow dish and pour the marinade over them, ensuring every piece is coated. Refrigerate for at least 1 hour or up to 24 hours before assembly. Discard any leftover marinade before baking.
Preheat your oven to 400℉ and prepare a rimmed baking sheet by lining it with foil and spraying it with non-stick cooking spray.
Lay each marinated chicken breast flat on a cutting board. Make four deep cuts across each breast about ½ inch apart, being careful not to slice all the way through.
Fill each cut in the chicken breasts with slices of tomato, mozzarella, and basil leaves.
Transfer your stuffed chicken onto the prepared baking sheet and bake for about 25–30 minutes or until an instant-read thermometer reads 165℉.
Allow your Caprese Stuffed Chicken to rest for about 5 minutes. Drizzle with balsamic glaze and sprinkle some extra chopped basil on top before serving.