Preheat the oven to 400 degrees.
Prepare the Tomato Salsa Cruda. Season the chicken and chayote with salt and pepper, place them in a baking dish, and roast for 30 to 35 minutes. Cool and remove the skin and bones from the chicken and tear into small strips. Cut the chayote into bitesize chunks. Toss the chicken and chayote with the Tomato Salsa Cruda and set aside.
To assemble the chalupas, place two crisp tortillas on each plate, overlapping them. Place the lettuce on top of the tortillas, then mound the chicken and chayote mixture on the lettuce. Garnish with the Cotija cheese, sour cream, and cilantro.
In a bowl, place the tomatoes, chilies, onion, lime juice, salt, and pepper. Mix well. Store in a covered container, in the refrigerator, no more than 1 day.
c.1997, M.S. Milliken & S. Feniger, all rights reserved