For a richer flavor, consider browning the chicken breasts in a skillet before adding them to the slow cooker. Adjust the amount of chili powder to your preferred level of spiciness. If you don't have heavy cream on hand, you can substitute it with half-and-half or milk, but the chili may not be as thick and creamy. Feel free to add other toppings to your white chicken chili, such as pickled jalapeños, crushed tortilla chips, or a dollop of guacamole.