Place the beef in a pot set over medium heat. Cook, stirring occasionally, until the beef is entirely cooked through. Drain away the excess fat, and then add salsa, stock and kidney beans. Bring to a gentle simmer, and simmer 15 minutes.
Preheat the oven to 350ºF. Spoon the mixture into a 9- x 13-inch or similar sized casserole. Sprinkle and spread the tortilla chips on top of the chili. Top the tortilla chips with the cheese. Bake the casserole 30 minutes, or until the cheese is melted and the filling bubbly. Sprinkle with cilantro or green onion, if using, and enjoy.