Preheat the oven to 350°F, and lightly grease a 9x13-inch baking dish.
Heat the oil in a large skillet over medium heat. Then add the onion and cook until it begins to soften and becomes translucent.
Add the beef and garlic and cook until the beef is cooked through, about 6-8 minutes. Stir in the diced tomatoes and taco seasoning until combined.
Next, add the sour cream and stir until well mixed. Add the corn, beans and 1 cup of the cheese until melted.
Transfer the mixture into the prepared baking dish and spread into an even layer.
Sprinkle the olives over the top, and sprinkle with the remaining cheese and crushed corn chips.
Bake for 20-25 minutes or until the cheese starts to bubble around the edges.
Serve with lime wedges, minced cilantro and sour cream if desired.
See post for tips, variations, and storage options.
Notes
*The calories listed are an approximation based on the ingredients in the recipe card and a serving size of 1 cup of casserole. Actual calories will vary.*For more information, tips, and answers to frequently asked questions, please refer to the post.*Photos courtesy of Karla Rae Photography.