In a large skillet over medium heat, brown the ground beef with the diced onion and minced garlic until the beef is fully cooked. Drain any excess fat.
Stir in the black beans, diced tomatoes, enchilada sauce, chili powder, cumin, salt, and black pepper. Simmer for about 5 minutes until heated through.
Meanwhile, cook the cheese tortellini according to package instructions. Drain and set aside.
Preheat your oven to 350°F.
In a large mixing bowl, combine the beef mixture with the cooked tortellini and half of the shredded cheddar cheese.
Spread a thin layer of the beef and tortellini mixture in the bottom of a 9x13-inch baking dish.
Fill each tortilla with the beef and tortellini mixture, roll them up, and place them seam-side down in the baking dish.
Pour any remaining beef mixture over the top of the enchiladas and sprinkle with the remaining cheddar cheese.
Bake in the preheated oven for 20-25 minutes, or until the cheese is bubbly and golden.
Remove from the oven and let cool for a few minutes. Garnish with chopped cilantro and serve with sour cream if desired.