Preheat oven to 350°. Brown ground beef, salt and pepper to taste. Add onion and green chilies and part of enchilada sauce. Heat tortillas in microwave 1 minute or until soft. Fill each tortilla with some meat mixture and cheese, rolling them and placing them side by side in a 9"x13" baking dish. Pour remaining sauce over the enchiladas and top with remaining cheese. Bake for 30 to 45 minutes or until cheese is melted and bubbly.