Preheat the oven to 350°F. In a large skillet, sauté the ground beef and onion with the taco seasoning, salt and pepper. Drain the meat mixture before adding seasonings. Spread the beef mixture in the bottom of a 9x13 baking dish, then sprinkle with the cheeses and chilies. In a bowl beat the eggs, milk and flour together, then pour over the beef and cheese layers. Bake until top is browned and eggs are set, 1 to 1½ hours. Let stand 5 minutes before cutting into squares and serving with lettuce, tomato and hot sauce.
Per Serving: 577 Calories, 40g Total Fat, 269mg Cholesterol, 864mg Sodium, 14g Carbohydrate, 0.4g Fiber, 37g Protein