Preheat your oven to 350°F.
In a large mixing bowl, combine the shredded chicken, cream cheese, sour cream, mayonnaise, garlic powder, onion powder, salt, pepper, and paprika. Mix until well combined and creamy.
Stir in 3/4 cup of the cheddar cheese and half of the green onions, if using.
Transfer the mixture to a greased 9x13-inch baking dish and spread it evenly.
Top with the remaining cheddar cheese and sprinkle the crushed crackers over the top.
Bake for 30-35 minutes, or until the casserole is bubbly and the top is golden brown.
Let it cool for 5-10 minutes before serving.