Preheat oven to 350°F; grease a 9x13-inch dish.
Cook beef and onion in large skillet over medium-high about 8-10 minutes until beef is browned and onion softened; drain excess fat.
Stir in taco seasoning, beans, corn, and tomatoes with chilies; simmer 5 minutes.
Mix sour cream and soup separately until smooth.
Layer half the chips, half the beef, half the sour cream mixture, and 1 1/2 cups cheese in dish.
Repeat with remaining chips, beef, sour cream mixture, and remaining 1 1/2 cups cheese.
Bake uncovered 25-30 minutes until hot and bubbly and cheese melted and lightly golden.
Stand 5 minutes; serve with salsa and optional toppings alongside.