Prepare the Chicken:

1. If not already cooked, poach the chicken breasts in a pot of simmering chicken broth until fully cooked (about 15 minutes). Remove, shred the chicken, and set aside. (Alternatively, you can use pre-cooked or rotisserie chicken.)

Sauté Aromatics:

1. In a large soup pot or Dutch oven, heat olive oil over medium heat.
2. Add the diced onion and minced garlic; sauté until the onion becomes translucent (about 3–4 minutes).

Build the Soup Base:

1. Stir in the tomato paste, ground cumin, chili powder, paprika, salt, and pepper. Sauté for another minute to let the spices bloom.
2. Pour in the chicken broth and diced tomatoes (with their juices). Add the bay leaf.
3. Bring the mixture to a simmer, then add the shredded chicken and black beans. Let the soup simmer gently for 20–25 minutes so that all the flavors meld.

Prepare the Tortilla Strips:

1. While the soup simmers, preheat your oven to 400°F (200°C) or heat a skillet over medium heat.
2. Cut corn tortillas into thin strips. Toss them lightly with vegetable oil or spray with cooking spray.
3. Spread the tortilla strips in a single layer on a baking sheet and bake for 8–10 minutes until crisp, or fry in a skillet until golden. Set aside.

Assemble and Serve:

1. Remove the bay leaf from the soup and adjust seasoning as needed.
2. Ladle the soup into bowls and top with crispy tortilla strips.
3. Garnish with diced avocado, chopped fresh cilantro, and a squeeze of lime. Add a dollop of sour cream if desired.