Optional: Grated monterey jack or pepper jack cheese, sour cream, heated refried beans, sliced black olives, and/or chopped sweet onions to garnish
Heat the oil in a large skillet over med-high heat. Add the chicken, onion, chile, chili powder, and cumin and cook, stirring frequently, until the onion is soft and the chicken is slightly crispy, about 8 minutes. Add the tomato sauce and salt & pepper. Keep warm while you prepare the salad.
Combine the lettuce, avocado, and vegetables in a large bowl. Toss with the dressing. Place the tortilla chips in a bowl. Put whichever garnishes you are using in separate bowls and serve buffet-style.