Preheat your oven to 350°F (175°C) and grease a 9x13 inch baking dish.

Combine 3 cups of shredded or cubed cooked chicken and 1 ½ cups of diced cooked ham in a large mixing bowl.

In a separate bowl, whisk together ½ cup sour cream, ¼ cup milk, 1 tablespoon Dijon mustard, ½ teaspoon garlic powder, ½ teaspoon onion powder, and salt and pepper to taste.

Pour the creamy mixture over the chicken and ham, stirring gently to ensure every piece is well-coated.

Transfer the mixture into your prepared baking dish, spreading it evenly across the bottom.

Sprinkle 1 ½ cups of shredded Swiss cheese evenly over the top of the casserole.

Mix ½ cup of bread crumbs with 2 tablespoons of melted butter and sprinkle over the cheese layer, if desired.

Bake for 25-30 minutes until the cheese is bubbly and golden brown.

Allow to cool for a few minutes before serving.