In a large pot, heat the olive oil over medium heat. Add the diced onion and cook for about 3-4 minutes until translucent. Stir in the minced garlic, red bell pepper, carrots, and celery, cooking for an additional 5-6 minutes until the vegetables begin to soften.
Sprinkle in the ground cumin, chili powder, smoked paprika, and cayenne pepper (if using), stirring to combine. Let the spices toast for about 1 minute until fragrant.
Pour in the chicken broth and canned fire-roasted diced tomatoes, stirring to mix everything well. Bring to a simmer.
Add the shredded chicken, black beans, and corn to the pot. Season with salt and pepper to taste. Simmer for another 15 minutes, allowing the flavors to meld together.
Just before serving, stir in the lime juice for that zesty kick. Adjust seasoning as necessary.
Ladle the soup into bowls, topping each with tortilla strips, avocado slices, a sprinkle of shredded cheese, and fresh cilantro. Add a dollop of sour cream if desired.
Dive into this warm, hearty soup and savor the cozy flavors that will warm your soul!