Heat olive oil in a large pot over medium heat. Add diced onion and sauté for about 5 until soft and translucent. Stir in minced garlic and diced bell pepper, cooking for an additional 2-3 minutes.
Pour in chicken broth and add shredded cooked chicken. Stir to combine the flavors.
Add undrained diced tomatoes, rinsed and drained black beans, and corn. Stir well to mix evenly.
Add ground cumin, chili powder, and smoked paprika. Stir for about 1 minute until fragrant. Season with salt and pepper to taste.
Bring the soup to a boil over medium-high heat, then reduce to low and let it simmer for 20-25 minutes.
Stir in chopped cilantro and lime juice just before serving. Ladle into bowls and garnish with crispy tortilla strips, avocado slices, and shredded cheese if desired.