Heat oven to 400 degrees. Lightly grease pie plate, 10 x 1 1/2 inches. Cook and stir ground beef and onion until beef is brown; drain. Stir in seasoning mix Spread beef mixture in pie plate. Sprinkle with chilies and cheese. Beat remaining ingredients until smooth, 15 seconds in blender on high speed or l minute with hand beater. Pour into pie plate. Bake until golden brown and knife inserted halfway between center and edge comes out cleans 25 to 30 minutes. Let stand 5 minutes before cutting. Refrigerate any remaining pie. 6 to 8 servings. High Altitude Directions (3500 to 6500 feet): Bake about 30 minutes.