Heat oven to 375°F. Spray 8-inch square (2-quart) glass baking dish with cooking spray. In medium bowl, mix tomatoes, corn and enchilada sauce.
In baking dish, layer half of the taco sauce with ground beef, 1 1/2 cups of the chips, 1/2 cup of the cheese and half of corn mixture. Top with remaining taco sauce with ground beef, 1 1/2 cups chips, 1/2 cup cheese and remaining corn mixture.
Sprinkle with remaining 1 cup cheese and the onions. Arrange remaining 1 cup chips upright around edge of dish, overlapping as necessary.
Bake uncovered 35 to 40 minutes or until bubbly and thoroughly heated.