Pre heat the oven to 400°F. Spray a 9-inch pie plate with non-stick cooking spray, set aside.
Brown ground beef and onion in a skillet over medium heat. Crumble well, drain any grease. Stir in seasoning mix and drained green chiles.
Spoon into pie plate. Using a spoon or spatula spread into an even layer.
In a medium mixing bowl, add bisquick, eggs and milk. Whisk until blended. Stir in half the shredded cheese. Pour over the meat mixture. Top with the remaining cheese.
Bake in the preheated oven for 30-35 minutes or until knife inserted in center comes out clean.
Cool 5 minutes. Run a knife around the outer edges of the pie plate before slicing. Top with your favorite taco fixings, enjoy!