Step 1

In a large, heavy-bottom pot or Dutch oven, heat the oil and cumin seeds over medium heat until the cumin is lightly toasted and aromatic, about 1 minute. Add onion, garlic, and bell pepper, and reduce heat to medium-low; cook, stirring occasionally, until vegetables are soft and lightly golden, about 10 minutes.

Step 2

Raise heat to medium, and add the chicken, chili powder, oregano, and bay leaf to pot. Cook, stirring frequently, until chicken is seared on the outside and coated thoroughly with spices, about 10 minutes. Add tomatoes and green chiles, and stir to combine. Cook 5 minutes. Add stock, salt, and beans; season with black pepper, and stir to combine.

Step 3

Cover; simmer. Stir contents, then replace lid to partially cover pot. Reduce heat to medium-low, and cook until chili is thickened and chicken is tender, stirring occasionally, about 1 1/2 hours.

Step 4

Divide chili among six bowls; garnish with sour cream and cilantro leaves, if desired. Serve immediately.