Heat the 1 tbsp (15ml) of olive oil in your Dutch oven over medium heat until it shimmers. Add the finely diced yellow onion and sauté for 4-5 minutes until translucent. Add the minced garlic, ground cumin, and dried oregano, cooking for exactly 1 minute until highly fragrant.

Pour in the 4 oz (113g) of diced green chiles, the 28 oz (794g) of green enchilada sauce, and the 4 cups (946ml) of chicken broth. Stir the mixture thoroughly. Bring the entire pot to a gentle, rolling boil over medium-high heat.

Carefully submerge the 1 lb (450g) of raw chicken breasts into the boiling broth. Reduce the heat to low, cover the pot with a tight-fitting lid, and let it simmer gently for 15-20 minutes until the internal temperature reaches 165°F (74°C).

Remove the cooked chicken breasts and transfer them to a clean cutting board. Using two forks, pull the meat apart into thick, visible chunks of shredded chicken. Return the chicken to the pot and let simmer uncovered for 5 minutes.

Ladle the hot soup into modern white ceramic bowls. Top each serving generously with a dollop of creamy white sour cream, a sprinkle of shredded white Monterey Jack cheese, and fresh, vibrant green cilantro leaves.