In a large bowl, combine tomatoes, basil, garlic, olive oil, balsamic vinegar, salt and pepper. Stir and refrigerate.
Make Chicken
Place chicken breasts on a cutting board, cover with a plastic wrap and pound lightly with a meat mallet or rolling pin until even thickness.
In a large bowl, add chicken breasts, olive oil, Italian seasoning, balsamic vinegar, salt and pepper. Stir to coat, cover and marinate in the fridge for 30 minutes.
Preheat grill on medium-high heat and oil grill grates with oil soaked paper towel. Grill chicken breasts covered for 10 minutes, flipping once. Chicken is ready when meat thermometer inserted in the center reads 165F.
Turn off heat, place cheese on top of each chicken. Cover the grill and let chicken stand until cheese has melted.
Transfer chicken onto a platter, spoon bruschetta on top and drizzle with balsamic glaze. Serve hot.
Notes
Store: Refrigerate leftovers in an airtight container for up to 3 days.Freeze: Freeze only chicken in an airtight container for up to 3 months. Bruschetta will not freeze or thaw well.