Heat a Dutch oven or soup kettle over medium-high heat. Toss chicken with salt, chili powder and 1 1/2 teaspoons of the oil to coat. Add chicken to hot pot; cook, turning only once, until impressively brown on both sides, 5-6 minutes. Transfer to a plate and cut (or shred when cool enough) into bite-size pieces.
Heat remaining tablespoon of oil in the hot empty pot; add onions and saute until softened, 4 to 5 minutes. Add garlic and peppers; continue to saute until fragrant about a minute longer. Add chicken broth, tomatoes and black beans. Bring to a boil, reduce heat to medium low. Simmer partially covered and skim foam as it surfaces, to blend flavors, about 5 minutes. Stir in chicken and turn off heat.
Place a portion of tortilla strips in each bowl, ladle over hot soup and top as desired, letting each person squirt in a little lime.
grated pepper jack cheese.
light sour cream.
chopped fresh cilantro.
hot red pepper sauce.
Make it quick: To speed cooking, heat the broth in the microwave while the onions and garlic are cooking.