Heat the olive oil in a large pot or Dutch oven over medium heat. Add the chicken breasts (or thighs) and season with salt and pepper. Cook for about 6-8 minutes per side until the chicken is golden brown and cooked through (internal temperature of 165°F/74°C). Remove from the pot and set aside.

1. In the same pot, add the sliced onion and bell peppers. Cook for 5-6 minutes, stirring occasionally, until the vegetables are tender and slightly caramelized.
2. Add the minced garlic and cook for another minute until fragrant. Sprinkle in the cumin, chili powder, paprika, and cayenne pepper (if using), stirring to coat the vegetables in the spices.
3. Pour in the chicken broth and diced tomatoes (with juices). Bring the mixture to a simmer and let it cook for 10-15 minutes to allow the flavors to meld.
4. While the soup is simmering, shred the cooked chicken using two forks or chop it into bite-sized pieces. Add the shredded chicken back into the pot.
5. Stir in the frozen corn and black beans (if using) and cook for an additional 5 minutes.
6. Taste the soup and adjust the seasoning with salt, pepper, or extra spices if needed. Just before serving, squeeze the juice of one lime into the soup.
7. Serve the soup hot, garnished with fresh cilantro, sliced avocado, and tortilla chips or strips for added crunch.