Combine chicken broth, garlic, honey, rosemary, salt & pepper in a medium bowl. This will become your marinade.
Add the 4 chicken fillets to the marinade bowl. Take the chicken and marinade and pour all into a gallon Ziploc/type bag. Press air out of the bag.
Refrigerate chicken 30-45 minutes. Any longer will start to breakdown the chickens proteins essentially starting the cooking process.
While chicken rests in marinade, grate mozarella cheese for topping.
Take chicken from marinade and place onto BBQ on medium heat. Cook approximately 4-5 minutes per side.
With 2 minutes left to cook on the second side, sprinkle mozzarella cheese onto chicken, to your liking, complete cooking.
Serve and Enjoy!