Step 1Heat a large pot over medium-high heat. Add the bacon and cook, turning occasionally, until it's crisp and the fat is rendered, 7 to 8 minutes. Transfer the bacon to a paper towel-lined plate, crumble and set aside. Add the onions, salt and pepper and cook over medium-high heat, stirring often, until deep golden brown and caramelized, about 20 minutes. Reserve half of the onions for the whole wheat flatbread recipe, or for another use.
Step 2Add the beer to the remaining onions, stir to scrape up any browned bits and continue to cook over medium-high heat, stirring occasionally, until the onions are moist and the beer is somewhat reduced, about 10 minutes. Stir in the chicken broth, lime juice, oregano, cumin, chiles, beans, salt and pepper, and bring to a boil over high heat. Reduce the heat to simmer and cook for 10 minutes. Puree the stew until smooth, using a blender (in batches) or in the pot with an immersion blender.
Step 3Add the corn, carrots, bay leaves and crumbled bacon to the stew and bring to a boil over medium-high heat. Add the chicken, reduce the heat to medium-low and simmer until cooked through, 20 to 25 minutes. Using a slotted spoon, transfer the chicken to a plate and set aside until it's cool enough to handle. (Meanwhile, leave the pot on the stove and allow the contents to simmer gently.) Shred the chicken, then return it to the pot.
Step 4Stir in one-fourth cup of the sour cream. Thin, if desired, with additional broth, season to taste and gently simmer for 10 minutes more, stirring occasionally. Remove from the heat and discard the bay leaves. You should have about 12 cups of stew. Ladle the stew into bowls, garnish with dollops of sour cream, if you like, and serve with tortillas on the side.