In a large skillet, bring oil to medium-high heat. Add onion and saute. Add ground beef and taco seasoning, and cook until done. Add tomatoes, beans, corn, and green chilis and combine well. Remove from heat
Building Your Dish
Spray a 9x13 baking dish with cooking spray. Spread approximately 1/3 can of enchilada sauce, or enough to cover bottom, in baking dish. Add a single layer of tortillas, overlapping slightly, to cover bottom of pan. Spoon 1/3 of meat mixture on top. Sprinkle 1/3 of cilantro, black olives and green onions on top. Sprinkle 1/3 of Monterrey Cheese and 1/3 of Co-Jack cheese. Repeat layers beginning again with enchilada sauce, and ending with cheese. Drizzle any remaining enchilada sauce on top. Bake at 350* F for 20 minutes, uncovered. Remove from oven and let sit for 10 minutes before cutting.