Preheat your oven to 350°F (175°C).
In a large skillet over medium heat, sauté the ground beef and chopped onion until browned and translucent (about 5-7 minutes). Drain excess grease.
Add minced garlic, chili powder, cumin, salt, and black pepper to the skillet, stirring for about 2 minutes.
Remove from heat and mix in 1/2 cup of enchilada sauce with the beef mixture.
Spread 1/2 cup of remaining enchilada sauce across the bottom of a 9x13 inch baking dish.
Fill each tortilla with approximately 1/4 cup of the beef mixture and a sprinkle of cheese, then roll tightly and place seam-side down in the baking dish.
Repeat until all tortillas are filled and arranged in the dish.
Pour the remaining enchilada sauce over the rolled tortillas and sprinkle with remaining cheese.
Bake for 20-25 minutes until cheese is melted and bubbling.
Allow to cool for 5 minutes before serving with sour cream and cilantro if desired.