Place potatoes into a medium size bowl with the oil, garlic salt and Mexican seasoning. Stir well to coat potatoes with oil and seasonings. Transfer to a large baking sheet and spread into a single layer.
Bake for 25 to 30 minutes, stirring several times, until crisp and golden brown.
Top with cheese, beans, tomatoes, olives, onions and chiles. Bake for 5 minutes more to melt cheese. Serve with salsa, guacamole and sour cream.