In a large Dutch oven, brown ground beef. Add onion and cook over low heat about 5 minutes or until onion is translucent. Add in garlic and cook an additional 2 minutes; stirring often.
Stir in marinara sauce, chicken broth and oregano. Reduce heat and simmer over low heat for 10 minutes.
Stir 1 cup of sauce into cooked pasta. Spoon ½ of ziti mixture into a 9X11-inch glass baking dish sprayed with cooking spray. Top with ½ cup Mozzarella cheese and 3 tablespoons Parmesan cheese. Ladle with ½ the sauce mixture, then repeat ziti, another ½ cup of Mozzarella cheese and 3 tablespoons of Parmesan cheese and remaining sauce.
Cover with foil and bake for 15 minutes. Remove cover and sprinkle with remaining cheeses. Bake an additional 10 minutes.