Preheat the oven to 400 degrees. Spray 8x8 dish with nonstick spray. Spread the crushed tortilla chips and 1/2 cup of the cheese on the bottom of the pan. Set aside.
Brown the beef and onions in a large skillet. Add the seasonings. Drain well.
Put the drained beef mixture on top of the tortilla cheese mixture in the baking dish. Top with 1/4 cup of taco sauce and more cheese.
Combine the baking mix, milk, and eggs and pour over the mixture in the baking dish.
Bake for 25 to 30 minutes or until a knife inserted in the center comes out clean. Top with remaining taco sauce and cheese and return to the oven for 5 to 10 minutes or until the cheese is melted.
Set aside to cool for 10 minutes before serving.