Line slow cooker with bag or spray with cooking spray.
Wash potatoes and zucchini. Peel the zucchini. Peel potatoes if desired.
Dice potatoes and peeled zucchini into small pieces. Dump into slow cooker.
Set chicken on top of the chopped vegetables. Sprinkle with salt and pepper.
Sprinkle garlic powder and thyme over the top of entire crockpot. Slice 2 tablespoons of butter into a few slices and lay on top of veggies and chicken.
Pour 3 cups chicken stock/broth/bone broth over top. Cover with lid and set to cook on low for 6 hours or on high for 3-4 hours.
Once chicken is fully cooked through, remove from the crockpot and shred. Set aside.
Add 3/4 cup milk and 1/4 cup sour cream (or 1 cup almond milk if you're keeping it dairy free!) to the crockpot and stir.
To blend soup, transfer a third of the soup toblender. Add half of the drained cannellini beans to the blender and blend until smooth. Pour into separate bowl. Add another third of the soup to the blender, along with the rest of the beans, and blend.
Pour blended soup back into crockpot. Add shredded chicken and stir. Season liberally with salt and pepper.
Serve with choice of toppings and/or bread for dipping.