Crumble ground beef into a 3-quart glass, microwave-safe, casserole dish; mix in garlic and seasoning blend. Cook on high, stirring halfway through, for 5 minutes. Drain.
Mix stewed tomatoes, rice, chopped onion, and minced onion into ground beef mixture. Cover and cook on high, stirring halfway through, until rice is cooked through, about 20 minutes. Let stand, covered, for 10 minutes. Stir and add mozzarella cheese.