Slice the chicken breasts in half horizontally to create two even thickness filets. Use a meat mallet to pound each filet to a thin even thickness.
In a small bowl, mix together 1 Tablespoon olive oil, Italian seasoning, white wine vinegar, 2 cloves garlic, salt, and pepper to make the marinade. Coat the chicken in the marinade, cover, and refrigerate for 6 hours.
Preheat the oven to 425 F (218 C). Bake the chicken on a rimmed baking sheet for 12 minutes (or until the internal temperature reads 165 F on a meat thermometer). Sprinkle the shredded mozzarella over the chicken. Turn the oven to broil, and broil for 1 – 2 minutes, or until the cheese is melted, golden brown, and bubbly.
Add the bruschetta topping ingredients to a medium bowl, and stir to combine. Spoon the topping over the cooked chicken, and serve immediately.