Place chicken breasts in the bottom of your slow cooker.
Add the rinsed and drained cannellini beans and great northern beans.
Stir in the diced green chilies, diced tomatoes and green chilies (with their juice), chicken broth, white chicken chili seasoning mix, cumin, garlic powder, and cayenne pepper if using.
Season with salt and black pepper.
Cover and cook on low for 6-8 hours or on high for 3-4 hours, until the chicken is cooked through and tender.
Remove chicken from the slow cooker and shred it with two forks.
Return the shredded chicken to the slow cooker and stir to combine with the chili.
Serve hot, with your favorite toppings.
Notes
For a spicier chili, add more cayenne pepper or a jalapeƱo pepper.
You can also use chicken thighs instead of breasts.