Preheat your oven to 375°F (190°C) and lightly spray a 9×13-inch baking dish with nonstick cooking spray.

In a skillet over medium heat, add the lean ground beef and finely chopped onion. Sauté for about 5-7 minutes until browned.

Warm the corn tortillas in the microwave for about 30-60 seconds to make them pliable.

Spoon a few tablespoons of the beef mixture into each tortilla, roll them up, and place seam-side down in the baking dish.

Pour the remaining enchilada sauce evenly over the rolled tortillas and sprinkle the shredded cheese on top.

Cover with foil and bake for 15 minutes, then uncover and bake for an additional 10 minutes until cheese is melted.

Let sit for a few minutes, then top with chopped cilantro, sliced green onions, or sour cream before serving.