Defrost/cook frozen meatballs according to directions on back of box in microwave, set aside.
Preheat oven to 375 F and spray 9x13" casserole dish with non stick spray. Pour half of spaghetti sauce on bottom.
Lay half frozen ravioli on top in single layer, top with cooked meatballs spread out, followed by half of remaining sauce + 1 cup of mozzarella cheese.
Layer rest of frozen ravioli, remaining sauce topped with rest of mozzarella with parmesan on top.
Cover top with foil and bake for 40 minutes, uncover and bake for 20 more minutes until top is golden brown. Let rest for 5 minutes before serving.