1. Bring a large pot of lightly salted water to a boil. Add cavatappi and return to a boil. Cook 6 minutes; drain.
2. Meanwhile, melt butter in a medium saucepan. Whisk in flour. While whisking, add milk in a thin stream. Whisk in paprika, salt and pepper. Bring to a simmer; cook 2 minutes.
3. Remove from heat and whisk in 2 cups of the cheddar. Fold cheese sauce into pasta.
4. Place half the macaroni and cheese in a baking dish. Microwave pulled chicken per package directions, about 6 minutes. Spoon over pasta in dish and top with remaining mac and cheese and 1 cup cheddar. Bake at 350 degrees for 20 minutes, until melted and bubbly.