In a small bowl, whisk together the cream of chicken soup, milk, oregano, pepper and garlic powder until smooth. Set aside.
Add the chicken breasts in an even layer in the slow cooker.
Add the ham over the chicken in an even layer, completely covering the chicken.
Next the Swiss cheese in an even layer, completely covering the ham.
Pour over the soup mixture and use a spatula to spread it out evenly over top of the cheese.
Sprinkle the cornbread stuffing mix on top, completely covering the soup mix.
Pour the melted butter evenly over the stuffing.
Cover and cook on LOW for 5 - 8 hours without opening the lid during the cooking time.
Serve and enjoy!