Sprinkle the buttered stuffing mixture evenly over the top of the chicken and sauce, covering the surface from edge to edge.
Cover the baking dish tightly with foil and bake for 25 minutes. This covered time allows the chicken to poach gently in the sauce and start to cook through.
Remove the foil and continue baking for another 20–25 minutes, or until the chicken is cooked through (an instant-read thermometer should read 165°F/74°C in the thickest part) and the stuffing is golden and slightly crisp on top.
Let the casserole rest for about 5–10 minutes before serving. This short rest allows the sauce to thicken slightly and makes it easier to portion without everything sliding apart.
To lean more deeply into traditional Southern flavors, you can swap the boxed stuffing for a cornbread stuffing mix or leftover homemade cornbread cut into cubes and tossed with a little poultry seasoning and melted butter. If you prefer dark meat, boneless, skinless chicken thighs work beautifully here and tend to stay extra juicy; just trim excess fat and proceed as written. For added vegetables, scatter a layer of sliced mushrooms, frozen peas, or a mix of frozen carrots and green beans over the chicken before you pour on the soup mixture—this turns the bake into more of a one-pan meal. If you’d like a bit more tang and richness, substitute Greek yogurt for half of the sour cream. For those watching sodium, choose low-sodium soup and broth, taste the sauce before adding extra salt, and opt for a reduced-sodium stuffing mix if available. Finally, if you enjoy a more pronounced herb profile, add a teaspoon of poultry seasoning or dried sage to the soup mixture, or finish the baked casserole with a shower of fresh chopped parsley or thyme for both color and freshness.