Step 1: In a large skillet, brown the ground beef over medium-high heat. Break it apart with a spoon as it cooks. Once fully browned, drain any excess grease thoroughly.
Step 2: Return the drained beef to the skillet. Stir in the diced onion, minced garlic, chili powder, cumin, smoked paprika, salt, and black pepper. Cook for 3-5 minutes, until the onion softens and the spices are fragrant.
Step 3: Add about 1 cup (half of one can) of the red enchilada sauce to the beef mixture. Stir well to combine. Remove from heat.
Step 4: Lightly spray the bottom of your slow cooker insert with cooking spray. Pour about 1/2 cup of enchilada sauce (from the remaining can) on the bottom of the slow cooker; spread evenly.
Step 5: Warm the corn tortillas according to package directions (microwave for 30 seconds or quickly heat in a dry skillet) to make them pliable and prevent cracking.
Step 6: Lay a warm tortilla flat. Spoon about 2-3 tablespoons of the beef mixture down the center. Sprinkle with about 1-2 tablespoons of shredded cheese. Roll the tortilla tightly and place it seam-side down in the slow cooker. Repeat with the remaining tortillas, beef mixture, and a portion of the cheese, arranging them in a single layer or two layers depending on your slow cooker size.
Step 7: Pour the remaining enchilada sauce (from the second can) over the rolled enchiladas, ensuring they are all covered. Sprinkle the remaining shredded cheese generously over the top.
Step 8: Cover the slow cooker and cook on LOW for 3-4 hours or on HIGH for 2-2.5 hours, until the tortillas are tender, the cheese is melted and bubbly, and the sauce is heated through. Serve hot with your favorite toppings.