Heat the olive oil in a large pot over medium heat. Add the diced onion and cook for about 5 minutes until softened. Stir in the minced garlic and cook for 1 minute. Add the tomato paste, chili powder, cumin, smoked paprika, and oregano, and cook for 30 seconds to toast the spices and deepen the flavor.
Pour in the chicken broth and fire-roasted tomatoes, stirring to combine. Submerge the raw chicken breasts in the broth, cover the pot, and simmer on low heat for 15-20 minutes, or until the chicken is fully cooked and reaches an internal temperature of 165°F.
Remove the chicken breasts and shred them with two forks. Return the shredded chicken to the pot and stir in the sweet corn. Let the soup simmer for another 5-7 minutes. Taste and adjust seasoning with salt and pepper as needed.
Serve hot, garnished with fresh cilantro and a squeeze of lime juice.