In a large pot or Dutch oven, heat olive oil over medium heat. Add chopped onion and cook until softened, about 5-7 minutes. Add minced garlic, chili powder, cumin, and smoked paprika, and cook for 1 minute more until fragrant.
Add chicken breasts to the pot. Pour in chicken broth and diced tomatoes (with their juices). Bring to a boil, then reduce heat and simmer, covered, for 20-25 minutes, or until chicken is cooked through.
Remove chicken from the pot and shred it using two forks. Return the shredded chicken to the pot.
Stir in the black beans and corn. Season with salt and black pepper to taste. Simmer for another 5 minutes to allow flavors to meld.
Ladle the soup into bowls. Garnish with shredded Monterey Jack cheese, chopped cilantro, tortilla strips, diced avocado, and a dollop of sour cream or Greek yogurt. Serve with lime wedges.
Notes
This soup is also delicious with shredded rotisserie chicken if you're short on time.