Preheat oven to 375°F (190°C). Spray a 9×13-inch casserole dish with nonstick spray and set aside.
Cook pasta in salted boiling water according to package directions until al dente. Drain and set aside.
In a large bowl, mix cream of chicken soup, half and half, Dijon mustard, parsley, seasoned salt, and black pepper until smooth.
Add Swiss cheese, diced chicken, and cooked pasta to the sauce. Stir until evenly coated.
Spread the mixture evenly into the prepared casserole dish.
In a small bowl, combine melted butter, panko breadcrumbs, and Parmesan cheese.
Sprinkle breadcrumb mixture evenly over the casserole. Bake uncovered for 25–30 minutes until bubbly and golden brown.
Let the casserole rest briefly before serving. Garnish with parsley if desired and serve hot.
