Combine Mazola® Corn Oil, balsamic vinegar, italian seasoning, and garlic powder in a gallon sized zip top bag and stir together.
Add the chicken breasts to the bag, close it and shake the bag around slightly to cover the chicken breasts in the marinade. Place bag in a dish and marinate in the fridge for 30 minutes.
While the chicken is marinating, slice both the mozzarella cheese and tomato into 6 even slices and preheat the grill to medium high heat or 375˚.
When the chicken is done marinating, remove it from the bag and cook on the preheated grill on one side for 5 minutes.
Flip the chicken over and top each breast with a heaping tablespoon of pesto, one slice of tomato, and then one slice of fresh mozzarella.
Close the grill and cook for another 4-5 minutes or until the internal temperature of each chicken breast reaches a minimum of 165˚. Cooking times may vary depending on the actual size and thickness of each chicken breast.