Warm up chicken in oven, pan or microwave, take care not to overcook the already-cooked chicken. You just want it warmed through. Lay chicken on baking sheet. Alternate slices of tomato and mozzarella on each piece of chicken. Drizzle olive oil over chicken. Set oven rack 8 inches below heat source. Broil for 3-4 minutes, until cheese begins to melt. Season mozzarella cheese and tomato with salt and pepper , drizzle a few drops of balsamic vinegar and sprinkle with fresh basil.
