Thaw if frozen. Pour contents of bag into casserole dish, then sprinkle with shredded mozzarella cheese (optional) and bake, covered, at 425 degrees for approx for 35-45 minutes (time may vary based on size of chicken--be sure to check before eating!)
You can cook in crock-pot for 4-6 hours on low or 2-3 hours on high (but we HIGHLY recommend using the oven--it gives it a much better flavor and texture!)