Add all the chicken marinade ingredients to a mixing bowl and whisk until well combined.
Add the chicken into a food storage bag, then pour the marinade over the top. Seal up the bag and make sure the marinade is coating all sides of the chicken. Place in the fridge for 1 hour.
To Make the Bruschetta
Once you heat up your grill, I recommend making the bruschetta and allowing it to sit at room temperature while you grill and rest the chicken. This will give it time for the flavors to meld.
Add the tomatoes, garlic, basil, olive oil, salt and pepper, into a medium bowl, then toss to combine. Set aside at room temperature while you grill the chicken.
Grill the chicken for several minutes on each side, until they reach an internal temperature on a meat thermometer of at least 165°F. Allow the chicken to rest at least 10 minutes before cutting into it.
Top each piece of chicken with some of the bruschetta and a drizzle of the balsamic reduction, then serve.