Preheat oven to 350°F and spray a 9x13-inch baking dish with cooking spray.
In a large skillet over medium-high heat, brown the ground beef with diced onion until meat is fully cooked and onions are softened, about 8-10 minutes, then drain excess fat.
Add minced garlic, chili powder, cumin, salt, and pepper to the beef mixture and cook for 1 minute until fragrant.
Stir in black beans, enchilada sauce, and diced tomatoes with green chiles, then simmer for 5 minutes.
Layer half of the tortilla strips in the bottom of the prepared baking dish, then top with half of the beef mixture and 1 cup of cheese.
Repeat layers with remaining tortilla strips, beef mixture, and top with remaining 2 cups of cheese.
Cover with foil and bake for 20 minutes, then remove foil and bake an additional 10 minutes until cheese is bubbly and lightly browned.
Let stand for 10 minutes, then serve topped with dollops of sour cream and fresh cilantro.