In a large skillet, brown sausage on medium-high heat. Drain sausage and discard drippings. Lower heat to medium. Add swiss chard and stir until just wilted.
Spray or lightly coat a 9x13 baking dish with olive oil. Spread rigatoni in the dish. Layer with 2 cups tomato sauce, provolone, sour cream, and sausage swiss chard mixture. Evenly sprinkle with basil, oregano, garlic powder, and pepper. Next layer with the mozzarella and remaining 2 cups tomato sauce. Top with Parmesan.
Bake 30 minutes until cheese is melty and casserole is thoroughly heated. Garnish with chopped fresh parsley and serve.