Preheat the oven to 375°F. Grease a 9x13-inch baking dish with butter or nonstick spray.
Toss the sliced chicken in the salt, garlic powder, onion powder, and pepper and add it to the prepared baking dish in a single layer.
1½ pounds boneless, skinless chicken breasts, ¾ teaspoon kosher salt, ½ teaspoon garlic powder, ½ teaspoon onion powder, ¼ teaspoon ground black pepper
In a bowl, whisk together the cream of chicken soup, sour cream, and 1 cup of chicken broth.
10.5 ounces cream of chicken soup, ¾ cup sour cream, 2 cups chicken broth
Pour the mixture over the chicken.
Add the stuffing mix to a bowl. Then, pour the remaining cup of chicken broth over the stuffing. Let it sit until saturated, about 5-10 minutes.
6 ounces dry chicken stuffing mix
Fluff with a fork.
Spoon the hydrated stuffing over the top of the chicken in the casserole dish in an even layer.
Melt the butter and drizzle it over the stuffing. Cover with aluminum foil and bake for 30 minutes.
4 tablespoons unsalted butter
Remove the foil and bake for an additional 20 minutes until the casserole is bubbling and the stuffing is browned and crispy on top.
Notes
*I used chicken breasts, but thighs also work well. **I like cream of chicken soup best, but cream of celery or cream of mushroom also work well.***Use your favorite brand--chicken or plain/vegetable both work well. Tips:
You can use fresh, homemade stuffing; but don't add any additional broth to it or it will turn out mushy.
Feel free to chop up some fresh mushrooms or frozen mixed vegetables (no need to thaw) and add them in with the chicken to bulk up this casserole.
You can also add steamed broccoli or sautéed carrots and onions. Cooking them first ensures they'll be fully cooked through in the casserole.
Do not press the stuffing down. Leaving it loosely on top allows for better browning and for steam to escape.
If you like your stuffing topping extra golden and crisp, place the casserole under the broiler for 1-2 minutes at the very end of baking.
Instead of freezing the entire casserole, you can scoop it into individual portions before freezing. This makes it faster to thaw and reheat for busy weeknight dinners.
Crockpot Instructions: Grease your crockpot, then layer in the casserole as directed. Drizzle the butter over top, cover, and cook on LOW for 4-6 hours or HIGH for 2-3 hours, or until the chicken is cooked through to 165°F and the stuffing is tender on top. Make-Ahead: You can assemble the casserole (minus the hydrated stuffing mix and butter) up to 24 hours in advance. Quickly hydrate the stuffing, top, and drizzle with butter before baking. You may need to add an extra 5-10 minutes to the bake time to make up for the cold start.Storage: Store chicken and stuffing casserole tightly covered with plastic wrap in the refrigerator for up to 3 days or in the freezer for up to 3 months.