Drain and rinse the beans. Separate the beans and roughly mash half of them with a potato masher. Set aside.
Heat the oil in a dutch oven or deep pot over medium high heat. Add the onions and peppers and sauté until they start to soften, about 5 minutes. Add the garlic and stir for 1 minute until fragrant. Add about 1 tsp salt and 1/2 tsp pepper to the vegetables. Add the cumin, chili powder and corriander and saute for about a minute to toast the spices. Stir in the chicken stock and lime juice and bring to a simmer. Add the beans and simmer on low for about 20 minutes.
Stir in the shredded chicken and cilantro. Taste for seasoning and add salt or pepper if necessary. Simmer about 5 more minutes until heated through.
Serve in large bowls topped with a dollop of sour cream and tortilla chips (optional).