Heat oil in a medium skillet. When very hot, fry tortilla strips in two batches until golden brown, about 1 minute. Transfer to paper towel-lined plate to drain. Set aside.
Transfer 2 tablespoons of the hot oil into a medium stockpot over medium-high heat. Add onion and garlic; sauté for 6-8 minutes. Add celery, tomatoes and TABASCO® Sauce; sauté for 5 minutes. Add chicken broth, oregano and cinnamon stick; simmer for 10 minutes. Stir in lime juice, lime slices and shredded chicken. Cook an additional 5 minutes. Salt to taste.
To serve, divide the soup into 6 bowls and top with tortilla strips. Garnish with cilantro and avocado. Serve immediately.
*You can easily make your own shredded chicken by boiling a whole cut-up chicken (approx. 4 pounds) with 1 quartered onion, 4 cloves peeled garlic, 1 stalk celery and 1/2 bunch of cilantro. Boil for 45-50 minutes or until cooked. When the chicken has cooled, pull the meat off the bone in large chunks, then shred to desired consistency. Discard skin and bones. Save the broth for any Mexican dish that calls for chicken stock.
Makes 6 servings.