1. Prepare the Aromatics: Begin by chopping your onion and mincing the garlic. These will form the aromatic base of your chili.

2. Combine Ingredients in Slow Cooker: Place the boneless, skinless chicken breasts at the bottom of your slow cooker. Evenly sprinkle the chopped onion and minced garlic over the chicken.

3. Add the Beans and Chiles: Rinse and drain both cans of cannellini beans and great northern beans, then add them to the slow cooker. Pour in the undrained can of diced green chiles.

4. Introduce Corn and Broth: Add the drained can of corn (or frozen corn) to the mixture. Pour in the low-sodium chicken broth, ensuring all ingredients are mostly submerged.

5. Season the Chili: Sprinkle the ground cumin, dried oregano, and optional cayenne pepper over the ingredients. Season generously with salt and freshly ground black pepper. Give everything a gentle stir to combine the spices.

6. Cook to Perfection: Cover the slow cooker with its lid. Cook on high for 4-6 hours, or on low for 6-8 hours, until the chicken is thoroughly cooked and easily shreds with a fork.

7. Shred the Chicken: Once cooked, carefully remove the chicken breasts from the slow cooker. Using two forks, shred the chicken into bite-sized pieces. Return the shredded chicken to the slow cooker and stir it back into the chili.

8. Serve and Garnish: Ladle the warm white chicken chili into bowls. Garnish with fresh chopped cilantro, a dollop of plain Greek yogurt or light sour cream, and diced avocado for a fresh, creamy finish.