Preheat oven to 375°F and spray a 9x13-inch baking dish with cooking spray.
Pour half of the marinara sauce and all of the diced tomatoes into the bottom of the prepared dish.
Arrange the frozen ravioli in a single layer over the sauce, then pour the remaining marinara sauce on top.
Sprinkle with garlic powder, Italian seasoning, and 1 cup of mozzarella cheese.
Cover tightly with aluminum foil and bake for 30 minutes.
Remove foil, top with remaining mozzarella and Parmesan cheese, and bake uncovered for 5 more minutes until cheese is melted and bubbly.
Let stand for 5 minutes before serving, garnished with fresh basil if desired.