Season the chicken with salt and pepper.
In a 12” skillet over medium-high heat, heat the oil.
Once the oil is hot, add the chicken breasts and cook for 6 to 7 minutes per side, or until the chicken is just cooked through. Remove onto a plate and allow to cool.
In a medium Dutch oven or 4-quart pot, heat the remaining tablespoon of oil over medium heat.
Once the oil is hot, add the onions and stir occasionally until softened. Turn down the heat a little if it’s too hot and your onion is beginning to burn.
Add the garlic, cumin, and oregano and stir gently and continuously for 30 seconds.
Add the enchilada sauce, black beans, both cans of tomatoes, chipotle peppers if using, and stock and stir to combine. Taste for salt and pepper and any other seasonings to adjust to taste.
Turn heat to medium-low and allow to simmer for 15 minutes, stirring occasionally.
While the soup is simmering, being careful if the chicken is still hot, shred the chicken. You can use 2 forks if the chicken is still too hot to use your fingers.
Once you have shredded your chicken and simmered the soup for 15 minutes, then add the shredded meat to the pot and stir to combine.
Taste for seasonings and add salt and/or pepper as desired.
Ladle the soup into the bowls and add desired toppings. Serve warm and thoroughly enjoy!