Place your chicken breasts in the bottom of your slow cooker. Feel free to cut them in half now or wait until after they're cooked. If you're adding onions, sprinkle them over the chicken.
In a separate bowl, whisk together the cream of chicken soup, light sour cream, dried parsley, garlic powder, black pepper, and water until smooth. This creates your savory, gravy-like sauce!
Pour this creamy mixture evenly over the chicken breasts in the slow cooker.
In another bowl, combine the dry stuffing mix with the melted butter. Stir or toss well until all the stuffing crumbs are nicely coated.
Sprinkle the buttered stuffing mixture over the chicken and creamy sauce. Close the lid on your slow cooker.
Cook on HIGH for 3-4 hours or on LOW for 5-6 hours, until the chicken is tender and reaches an internal temperature of 165°F.
Once done, the chicken will be perfectly tender. Serve this hearty casserole warm and enjoy your effortless, delicious meal!