My aunt brings this ultimate cozy casserole to every Sunday dinner and there are never leftovers.

Because this recipe is built on four core ingredients, any variations should be thoughtful so you keep the spirit of a simple, cozy casserole.
For a slightly richer flavor, swap one can of cream of chicken soup for cream of mushroom—this adds an earthier note without changing the process. If you prefer darker meat, you can use boneless, skinless chicken thighs in place of breasts; they stay especially juicy after several hours in the slow cooker.
To encourage more browned, toasty bits in the stuffing, crack the slow cooker lid open slightly for the last 20–30 minutes of cooking, which lets some steam escape and dries the top just enough. If your stuffing looks a bit dry toward the end, drizzle in a few extra tablespoons of warm chicken broth around the edges (not over the entire top) to keep the texture moist and fluffy.

For those cooking ahead, you can assemble the dish (chicken, sauce, and stuffing on top) in the insert, cover, and refrigerate up to 12 hours; let it sit at room temperature while you preheat the slow cooker, then cook as directed, adding up to 30 minutes to the total time if everything went in cold.
Finally, if you like a little color when serving, garnish individual plates with chopped fresh parsley or chives—added at the end so they don’t count as a core ingredient in the base recipe but still bring a fresh contrast to the creamy, comforting casserole.