Heat the olive oil in a large, deep skillet (one with a tight-fitting lid) over medium high heat. Once the oil is hot, add the patties to the skillet. Let them cook until golden on the bottoms, about 4-5 minutes. Then flip them. Lower the heat down to medium and add the marinara to the skillet all around the patties. Sprinkle 2 tbsp. of mozzarella over each patty, then place the lid on and let this cook until the chicken is completely cooked through, about 10-12 additional minutes.