In a large pot, heat a tablespoon of olive oil over medium-high heat. Add the diced red onion and finely chopped jalapeño, stirring occasionally for about 3-4 minutes until the onions become translucent. Add minced garlic and cook for an additional 30 seconds.

Incorporate the boneless skinless chicken breasts, fire-roasted corn, and Tajín seasoning, cumin, chili powder, salt, and pepper. Stir well to combine.

Pour in low-sodium chicken stock to cover the mixture, raise the heat to boiling, then reduce to low and cover the pot. Simmer for 25 minutes until the chicken is cooked through.

Remove the cooked chicken, shred it into pieces, and return it to the pot.

Reduce heat to low, stir in sour cream, Monterey Jack cheese, and lime juice. Simmer gently for 3 more minutes.

Ladle the soup into bowls, garnish with crumbled queso fresco and cilantro. Serve hot with lime wedges and tortilla chips.