Preheat oven to 375°F (190°C) and lightly grease a 9x13 inch baking dish.
In a large skillet over medium-high heat, add the vegetable oil. Sauté the diced onion until translucent, about 3-4 minutes.
Add the ground beef to the skillet. Cook until browned, breaking it apart with a spatula. Drain any excess fat.
Stir the chili powder, ground cumin, garlic powder, salt, and 1/2 cup of the red enchilada sauce into the beef mixture. Simmer for 3 minutes, then remove from heat.
Spread 1/2 cup of the enchilada sauce on the bottom of the prepared baking dish.
Assemble the enchiladas: place about 1/3 cup of the beef mixture and 2 tablespoons of cheddar cheese in the center of each tortilla. Roll tightly and place seam-side down in the baking dish.
Pour the remaining enchilada sauce evenly over the rolled tortillas. Sprinkle the rest of the cheddar cheese on top.
Bake uncovered for 20 minutes, or until the cheese is melted and bubbly.
Garnish with sour cream and chopped fresh cilantro before serving.