Slightly modified from the recipe from 55 restaurant in Columbus, OH.
Recipe can be halved.
Pour beans and stock into a large stock pot and bring to a simmer. Puree half of the beans. Stir the cayenne into the pureed beans. Set aside.
In another large pan, warm the olive oil. Add chicken and cook, stirring frequently, until lightly browned. When cooked, add chicken to the pot.
Without cleaning the pan, add onion, garlic and chili pepper. Cook until onion is translucent, stirring frequently. Add the onion mixture to the pot. Bring to a boil. Reduce heat. Add pureed beans. Add cream. Heat through, stirring often, allowing soup to reduce slightly. Season to taste with salt and pepper.
To serve, ladle soup into heatproof bowls. Top with tortilla chips and cheese. Place under broiler until cheese melts, if desired. Garnish with cilantro, if desired.