Preheat the oven to 350°F.
Grease a large 9x13 baking dish with cooking spray. Add the beans, corn, tomatoes with green chili, bell pepper, taco seasoning, salt, chicken, sour cream, and ¾ cup of the cheese, stirring until well combined.
Smooth the mixture into an even layer, then top with the corn chips and remaining ½ cup cheese.
Cover with foil and bake for 20 minutes, then uncover and bake 5-10 more minutes, until brown and bubbling.
Let sit for 5-10 minutes to set, then serve with toppings if desired.
