Creating Swiss Chicken Casserole is straightforward if you follow these simple steps:

1. Preheat the Oven: Preheat your oven to 350°F (175°C).
2. Prepare the Chicken: Season the chicken breasts with salt, pepper, garlic powder, and onion powder. Place them in a greased 9×13-inch baking dish.
3. Mix the Sauce: In a medium bowl, combine the sour cream and cream of chicken soup. Mix well until smooth.
4. Add Cheese: Fold in half of the shredded Swiss cheese into the sauce mixture.
5. Spread the Sauce: Pour the sauce evenly over the seasoned chicken breasts in the baking dish.
6. Combine Breadcrumbs: In a separate bowl, mix the breadcrumbs with melted butter. Stir until all crumbs are coated.
7. Top the Casserole: Sprinkle the breadcrumb mixture over the sauce-covered chicken.
8. Bake: Place the baking dish in the preheated oven and bake for 40-45 minutes or until the chicken is cooked through and the topping is golden brown.
9. Cool: Remove the casserole from the oven and let it cool for about 5-10 minutes before serving.
10. Garnish: Sprinkle with fresh parsley if desired for added color and flavor.

Following these steps will guide you in creating this incredible casserole effortlessly.