Preheat oven to 425°F. Coat 2 baking sheets and a shallow 3-quart baking dish with nonstick cooking spray.rush oil lightly over one side of each tortilla. Sprinkle with salt. Cut each tortilla into 8 wedges and arrange in a single layer on the prepared baking sheets. Bake until crisp, 8 to 10 minutes, rotating the baking sheets midway through baking. Let cool.
Reduce the oven temperature to 375°F. Stir together chili, pinto beans, enchilada sauce, tomato sauce, onions and 3/4 cup of the cheese in a large bowl. Add 4 cups of the tortilla crisps and stir to coat them with sauce. Turn into the prepared baking dish and bake until bubbly, 25 to 30 minutes.
Mix together sour cream and yogurt in a small bowl and spread over the top of the casserole. Sprinkle with the remaining 1/4 cup cheese and 2 cups tortilla crisps. Bake for 5 minutes longer.