Preheat oven to 350°F (177°C). Spray a 9X13 inch baking dish with nonstick cooking spray, Spray a piece (large enough to cover the baking dish) of aluminum foil with cooking spray. Place on counter sprayed side up; set aside.
In a large skillet, cook and crumble ground beef, (1 pound) over medium-high heat, until browned and crumbly, 8 to 10 minutes.
Stir in taco seasoning (1 envelope) and salsa (1 jar), reduce the heat, and simmer until liquid is absorbed about 8-10 minutes.
Stir in chili beans (1 can) and corn (1 cup) and cook until heated through.
Arrange 6 tortillas in the bottom of the dish, overlapping the tortillas.
Spoon half of the meat mixture over the tortillas then sprinkle with half the cheese.
Repeat a second layer of tortillas on top of the casserole. Pour the remainder of the meat mixture over the tortillas, spread the sour cream (2 cups) over the top, then sprinkle olives (1 cup), 1/2 cup green onion, and tomatoes (1 cup). Top with an even layer of the remaining cheese.
Bake in preheated oven for 40-45 minutes or until heated through. Remove foil, and continue to bake, uncovered for 10 minutes.
Sprinkle top with cilantro (1/2 cup) and remaining 1/2 cup green onion. Serve.