After you've strained the stock, wipe out the stockpot and return to the stove.
Heat the remaining 1 tablespoon oil over medium heat.
Add the diced onion and serrano peppers and cook for 5-6 minutes until the onions begin to soften slightly.
Pour in the huitlacoche and cook for 5 minutes more. Season lightly with salt and pepper.
Add the shredded chicken and chicken stock and bring to a boil.
Season with the remaining cumin seeds, chili powder. paprika, and Mexican oregano. Season to taste with salt and pepper.
Add the chopped poblano peppers along with roasted corn and sweet potatoes.
Simmer for 15-20 minutes to allow the flavors to meld and then season to taste. If the soup doesn't have enough broth, add a bit more water, 1 cup at a time, and simmer an additional 10 minutes.