Heat 1 tablespoon olive oil in a large skillet over medium heat. Add the diced onion and sauté for 3–4 minutes until softened and translucent.

Add the minced garlic and cook for 1 minute, stirring frequently.

Add the ground beef to the skillet, breaking it apart with a spatula. Cook for 5–7 minutes until browned and no longer pink. Drain excess fat if necessary.

Stir in the black beans, diced tomatoes with green chilies, and taco seasoning. Mix well and simmer for 5 minutes. Season with salt and pepper to taste.

Bring a large pot of salted water to a boil. Cook the cheese tortellini according to package instructions (about 3–5 minutes) until they float to the surface. Drain and set aside.

Preheat the oven to 350°F (175°C).

In a large mixing bowl, gently combine the cooked tortellini with the beef mixture.

Spread a thin layer of enchilada sauce on the bottom of a 9×13-inch baking dish.

Add the tortellini and beef mixture, spreading it evenly.

Pour the remaining enchilada sauce over the top.

Sprinkle shredded cheddar cheese evenly over the dish.

Cover with aluminum foil and bake for 20 minutes.

Remove the foil and bake for another 10–15 minutes, until the cheese is melted, bubbly, and lightly golden.

Let cool for 5 minutes, then top with sour cream and fresh cilantro before serving.