Preheat oven to 350° and spray a 3 quart baking dish with a non stick spray. Set aside.
In a medium saucepan, add shredded roast, ½ of the black olives, diced green chilies, ⅓ of red chili sauce. Heat over low flame until hot.
In another saucepan, heat ⅓ of sauce just until warmed then dip each tortilla into the sauce making sure each is covered in sauce.
Place a layer of tortillas in the bottom of the baking dish.
Spoon ½ meat mixture, ½ sour cream, ⅓ grated cheese onto tortillas.
Add another layer of tortillas, remaining meat mixture, sour cream and sprinkle with another ⅓ grated cheese.
Next, place remaining tortillas, cheese, and pour the remaining red chili sauce, and any sauce left in the saucepan, over the cheese.
Top with black olives.
Cover with lid, or foil, and bake for 45 minutes or until cheese is melted and bubbly.
Remove from oven and top with sour cream, cilantro, green onions and avocado if desired.
Enjoy!