Preheat your grill to medium-high heat.
In a large bowl combine oil, Italian seasoning, salt and black pepper. Add the chicken and coat evenly.
Place the chicken breasts on the preheated grill and cook for about 6-8 minutes per side or until the internal temperature reaches 165°F (75°C).
Meanwhile, combine all the bruschetta ingredients and mix well.
Once the chicken is cooked through, top each breast with a slice of mozzarella cheese, then cook for 1-2 minutes until the cheese is melted.
Remove the chicken from the grill and let it rest for a few minutes. Then, spoon the tomato-basil bruschetta mixture generously over each chicken breast, and garnish with additional fresh basil leaves, if desired.