Preheat your oven to 375 degrees Fahrenheit (190 degrees Celsius). If your stuffing mix isn’t already toasted, you can quickly toast it in a dry pan for extra crunch, but it’s not required.

In a large mixing bowl, combine the shredded chicken, cream of chicken soup, milk, peas, garlic powder, salt, and pepper. Stir until everything is evenly coated and the mixture looks creamy.

Pour the creamy chicken mixture into a greased 9x13 inch baking dish. Sprinkle the prepared stuffing evenly over the top. The layer should be fairly even, but a few chunky bits are fine.

Bake for about 25 to 30 minutes, until the casserole is hot throughout and the stuffing topping is lightly golden. If you like a crisper top, you can broil for 1–2 minutes at the end, watching closely so it doesn’t burn.

Remove from the oven and immediately sprinkle the cheddar cheese over the hot casserole. Let it melt for a couple of minutes, then give it a gentle stir if you prefer a uniform cheesy layer. Garnish with dried herbs if you’re using them.