Preheat your oven to 350°F (175°C).
Grease a 9x13 inch baking dish.
Butterfly the chicken breasts and place them in the dish.
Layer each chicken breast with a slice of ham and a sprinkle of Swiss cheese.
In a bowl, mix the cream of chicken soup and milk until smooth.
Pour the soup mixture evenly over the chicken.
In another bowl, combine breadcrumbs, garlic powder, paprika, salt, and pepper.
Sprinkle the breadcrumb mixture over the casserole.
Drizzle melted butter on top of the breadcrumbs.
Bake in the preheated oven for 40-45 minutes, or until the chicken is cooked through and the top is golden brown.