Set sauce aside. In a new large skillet, brown ground beef with the onions over medium-high heat. Drain the fat, add salt and pepper to taste, and stir in 1 cup of Colorado Chile Sauce. Set aside.
Preheat the oven to 350 degrees F.
Spread 1/2 cup of the Colorado Chile Sauce in the bottom of a 9- by 13-inch baking dish.
Next, one at a time, add meat mixture to a tortilla and add a generous amount of shredded cheddar cheese - about ¼ cup per tortilla. Roll up the tortilla with the filling inside.
Place the tortilla seam side down in the baking dish. Repeat with the remaining tortillas and pour the remaining Colorado Chile Sauce over the top. Sprinkle the remaining cheese, about 2 cups, over the enchiladas.
Bake the enchiladas for 30 minutes or until bubbly. Serve with your choice of toppings listed above.
We like to serve these individually - that way each person can add as much or as little sauce as they would like or even add their favorite fillings, like jalapenos, roasted chiles, or peppers. Prepare the same way as directed above, placing 2 enchiladas on each plate. Bake for 20-30 minutes or until hot and bubbly.