In a large, deep skillet (10 inches or larger), brown the ground beef over medium-high heat, seasoning with salt and pepper. Drain excess grease if needed. Add the taco seasoning and 1/3 cup water, stirring until the sauce thickens.
Stir in the enchilada sauce, drained corn, and black beans until combined.
Add the uncooked elbow macaroni, milk, and beef broth. Stir well and bring to a gentle simmer. Cover and cook for about 12–15 minutes, stirring frequently to prevent sticking. Add more broth or milk as needed until the pasta is tender and the sauce is creamy.
Once the pasta is cooked, sprinkle the shredded cheddar cheese over the top. Cover for a couple of minutes until the cheese melts, or place the skillet under the broiler briefly if your skillet is oven-safe.
Finish with a scoop of sour cream and fresh green onions. Add your favorite taco toppings, such as pico de gallo, avocado, guacamole, fresh cilantro, or crushed tortilla chips.