Combine dried beans, chicken, salsa, onion, cumin, salt, chili powder, broth, and water in the bowl of a 6-quart slow cooker and give it a stir to combine. Cook until the beans are tender and the chicken falls apart easily, 4 hours on high or 7-8 hours on low. (Note: dried beans can vary in cook time depending on how long they've been stored, so plan for the higher end of the cook time range if you think yours might have been on the shelf or stuck in the back of the pantry for a bit.)
Remove chicken from the slow cooker and transfer to a cutting board.
Optional step to thicken (see note): Remove 1 cup of liquid from the chili. Whisk 1 cup sour cream into this cooking liquid. Pour the thickened liquid back into the chili and stir to combine.
Roughly chop the chicken and stir it back into the chili.
Taste the chili and season with some more salt, if needed.
Ladle soup into bowls and serve with any (or all!) the toppings you like.