Spray a 6-quart (or larger) slow cooker with nonstick cooking spray.
Season the chicken – Place chicken breasts in the crock pot and pour in the chicken broth. Sprinkle half of the sage, rosemary, salt, and pepper over the chicken.
Make the creamy layer – In a bowl, stir together sour cream and cream of chicken soup. Spread evenly over the chicken.
Prepare the stuffing – In another bowl, mix the stuffing, remaining seasonings, onion, celery, and garlic. Sprinkle this mixture over the soup layer (do not stir). Place bay leaves on top.
Cover and cook on low for 4 hours or high for 2 hours.
Uncover, place drained green beans on top of the stuffing, and season with salt, pepper, and garlic powder to taste.
Finish cooking – Cover again and cook 30 minutes on low or 15 minutes on high until the green beans are heated and the chicken reaches 165°F.
Plate the chicken with stuffing and green beans, remove the bay leaves, and dig in!