Preheat oven to 350°F. Brown hamburger meat and diced onion; drain. As hamburger meat is cooking, heat the chili.
Take a flour tortilla and spoon in hamburger meat, some enchilada sauce, green onions and some shredded cheese. Place in baking dish. Continue till all hamburger meat is used.
Top with heated chili, remainder of enchilada sauce, remainder of chopped green onions and shredded cheese.
Cover with foil and bake for 20 minutes. Remove foil and continue baking for approximately 10 minutes, or until all cheese is melted and enchiladas are heated through. Serve with Mexican rice, salsa and sour cream, if desired.