Preheat the oven to 350 degrees F. Brush a 9 x 9 baking dish with 1/2 tablespoon avocado or olive oil using a pastry brush and set it aside.
Put 2 sleeves Ritz crackers in a large bowl and crush them with clean hands until they're fine crumbs.
Pour 1/2 cup unsalted butter over the crumbs and stir until every crumb is coated. Set aside.
In a second large bowl, combine 1 can cream of chicken soup, 1 cup shredded Cheddar cheese, 1 cup sour cream, 4 ounces cream cheese, 1 teaspoon Dijon mustard, 1/4 cup green onions, 1/4 cup yellow onion, 4 ounces diced green chiles, 2 tablespoons of the parsley, 1/2 teaspoon onion powder, 1/2 teaspoon garlic powder, 1/2 teaspoon paprika, 1/4 teaspoon coarse kosher salt, and 1/4 teaspoon pepper. Stir until smooth and well combined.
Add 3 cups cooked chicken and stir until it's fully coated.
Spread the chicken mixture evenly in the prepared baking dish.
Sprinkle the buttered cracker crumbs evenly over the top.
Bake uncovered for 30 minutes, until the top is golden brown.
Sprinkle with the remaining 1 tablespoon of parsley and serve.
Notes
To double the recipe, use a 9 x 13 baking dish and bake for the same 30 minutes.