Love this Tortilla Soup.  It is fast and delicious.  

Heat 1 tbs. canola, vegetable or olive oil in large pot over medium heat.  Add 1 medium chopped onion.  Reduce heat to medium-low, and cook until soft and lightly browned, about 5 minutes.  Stir in 1 large clove minced garlic and 2 teaspoons chili powder until aromatic, about 15 seconds. 

Add 2 qts low sodium chicken broth, raise the heat to high, and bring to a boil.  Now reduce heat to low and add 2 tablespoons lime juice,  and 12 ounces whole boneless and skinless chicken breast, cut in half.  Partially cover and gently simmer until the chicken is no longer pink, about 15 minutes.

Use a slotted spoon to remove the chicken from the stock; cool slightly.  Shred chicken into bite-sized pieces.  Reserve.  Add 1 (one) 14 1/2 oz can diced tomatoes, drained to stockpot.  Cook over medium heat until stock is very hot, about 5 minutes.  

To serve, divide the shredded chicken, 6 flour tortillas that have been cut in half and then crosswise sliced into 1/8″ wide strips, and 2 medium ripe avocadoes that have been peeled, pitted and cut into 1/2′ dice.  Place some of each in bottom of each bowl and ladle hot stock on top.  Top each bowl with 1-2 tablespoons of grated mild white cheddar or monterey jack cheese (1 1/2 cups total), and a generous sprinkling of fresh cilantro leaves (1/2 cup packed total).  Place 2  medium jalapeno peppers, halved, seeded and sliced thin, remaining cheese and lime wedges on the table for adding to individual bowls, as desired. 

Variation:  Omit flour tortillas and substitute 6 corn tortillas that have been sliced into 1/8″ strips, frying in 2 cups hot canola oil for 6 minutes.  Drain on paper towels.  Ladle hot soup into bowls, (omiting flour tortillas) sprinkling fried corn tortillas on top with cheese and cilantro.  Place remaining fried tortilla strips on table with other garnishes.