Preheat oven to 350 degrees F (175 degrees C). Spread the olive oil in a 9x13 inch baking dish.
Arrange chicken in the dish, and cover with the dressing. It's best to place chicken pieces close together so that the cheese and the dressing do not burn on the bottom of the pan.
Bake for 20 minutes in the preheated oven. Remove from heat, top with mozzarella cheese, and return to the oven. Continue cooking for about 15 minutes, until the cheese is melted and lightly browned and the chicken is no longer pink and juices run clear.