In a large pot, heat the oil over medium heat. Add the onion, garlic, and jalapeño and cook, stirring frequently, until softened, about 5 minutes. Add the flour, chili powder, cumin, and oregano and stir until you can smell the spices.
Add the green chilies and chicken and continue to cook, stirring occasionally, until the chicken starts to turn white, about 3 minutes. Turn the heat up to medium-high and add the broth, beans, and season with salt and pepper. Bring to a simmer and cook for about 15 minutes, stirring occasionally and lightly crushing some of the beans with a spoon against the side of the pot to thicken the chili.
Remove from the heat and stir in the sour cream. Ladle into bowls and garnish with the desired toppings.
Notes
The sour cream is added at the end of the cooking time and stirred in off the stove, which prevents it from making the sauce separate. This is ideal, so if you are planning to make the chili ahead of time, hold back on adding the sour cream. You can then store the chili in the fridge for up to 4 days or freeze it in an airtight freezer-proof container for up to 6 months.When you reheat the chili, don’t add the sour cream until the chili is hot. Then reheat the chili in a pot over medium heat, stirring frequently. Stir in the sour cream and serve.If you have leftover chili with the sour cream already added, that’s fine! Just make sure to reheat the chili over low heat just until it’s warmed throughout. Don’t let the chili come to a boil or even a rolling simmer. You just want the chili to be heated through, and that will give you the best consistency without the sauce breaking. But if the sauce starts to separate, that’s ok! It will still taste great.