Cut the corn tortillas into thin strips.
Pan method: Heat 1–2 tablespoons oil in a skillet over medium. Add strips in batches and cook until golden and crisp, 3–4 minutes. Transfer to a paper towel–lined plate and sprinkle with salt.
Bake method: Toss strips with a little oil and salt. Bake at 400°F for 8–10 minutes, flipping once, until crisp.
Warm olive oil in a large pot over medium heat. Add onion and a pinch of salt. Cook until translucent, 4–5 minutes.
Stir in garlic and jalapeño. Cook 30–60 seconds until fragrant.
Sprinkle in chili powder, cumin, smoked paprika, oregano, salt, and pepper. Stir 30 seconds to bloom the spices.
Stir in tomato paste and cook 1 minute to darken slightly.
Add diced tomatoes and chicken broth. Bring to a gentle boil.
Lower heat to a simmer. Add the chicken breasts or thighs to the pot.
Simmer uncovered until the chicken cooks through and turns tender, 12–18 minutes depending on thickness.
Transfer chicken to a cutting board and shred with two forks.
Return shredded chicken to the pot along with black beans and corn. Simmer 5 minutes to warm through and meld flavors.
Stir in fresh lime juice. Taste and adjust salt, pepper, and lime.
Use 3 cups shredded rotisserie chicken. Skip the poaching step. Add chicken during the last 5 minutes of simmering.
Ladle soup into bowls. Top with tortilla strips, avocado, cilantro, cheese, a dollop of sour cream, and a squeeze of lime.
Offer hot sauce at the table for spice lovers.
