In a large mixing bowl, combine the shredded chicken, gluten-free cream of chicken soup, sour cream, cheddar cheese, green onions, garlic powder, salt, and pepper.
Transfer the mixture to a greased 9×13 inch baking dish.
In a separate bowl, mix the gluten-free breadcrumbs with melted butter until well combined.
Sprinkle the breadcrumb mixture evenly over the chicken mixture in the baking dish.
Bake in the preheated oven for 30-35 minutes, or until the casserole is bubbly and the top is golden brown.
Let it cool for a few minutes before serving.
Notes
For a spicier version, add diced jalapeños to the chicken mixture.
Can substitute cooked turkey for chicken if desired.
Make sure all ingredients are certified gluten-free.