Preheat the oven to 350 degrees. Grease a 9 x 13 inch casserole dish with cooking spray.
Cook the pasta. Bring a pot of salted water to a boil. Add pasta and cook until al dente. Drain, then set aside.
Brown the beef and onions. Meanwhile, heat the oil in a large skillet over medium high heat. Add the beef, breaking it up into large chunks and spreading it evenly across the pan. Allow to brown, undisturbed, for about 3 minutes, then flip and continue to cook until browned on all sides, about 7-8 minutes total. Add the onion and saute until softened, another 5 minutes. Drain off any excess grease then sprinkle the mixture with taco seasoning.
Add sauces. Stir in the tomato sauce, tomatoes and green chilies, sour cream, and frozen corn. Heat through, taste, then season as needed with additional salt and pepper.
Combine. Add the ground beef mixture to the cooked pasta, stirring to combine.
Add cheese and bake. Spread the mixture in the prepared pan, then top with cheese. Bake for 25 minutes, or until cheese is melted and browned.
Serve with your favorite taco toppings!