Prepare the Chicken: Place chicken breasts in a large pot and cover with water. Bring to a boil, then reduce heat and simmer for 15-20 minutes, or until chicken is cooked through. Remove chicken from pot and let cool slightly. Shred the chicken with two forks.

Sauté Aromatics: Heat olive oil in a large pot or Dutch oven over medium heat. Add onion and cook until softened, about 5 minutes. Add garlic and jalapeño (if using) and cook for another minute until fragrant.

Add Vegetables: Stir in green bell pepper and cook for 3-4 minutes, until slightly softened.

Combine Ingredients: Add the shredded chicken, great northern beans, cannellini beans, diced green chiles, chicken broth, cumin, oregano, chili powder, and cayenne pepper (if using) to the pot.

Simmer: Bring the mixture to a simmer, then reduce heat and cook for at least 30 minutes, or up to an hour, to allow the flavors to meld. The longer it simmers, the better it will taste!

Blend (Optional): For a creamier texture, use an immersion blender to partially blend the chili. Be careful not to over-blend; you want to retain some chunks of beans and chicken. Alternatively, you can remove about 1 cup of the chili and blend it in a regular blender, then return it to the pot.

Finish and Serve: Stir in the cilantro and lime juice. Season with salt and pepper to taste. Serve hot, topped with a dollop of Greek yogurt (if desired).