Preheat oven to 375° F and butter a 2 quart casserole dish. Fill a large (6 quarts) pot with water with 3 - 4 tablespoons salt. Heat to simmering and hold.
Warm the milk to a low simmer in a small saucepan, or heat in a microwavable bowl until milk is just beginning to steam, about 115° F.
Combine the Nutmeg, Paprika, Sugar, Onion Powder, Ground Black Pepper and salt in a small bowl. Stir the Hot Sauce and seasonings into the flour sauce and cook over low to medium heat until sauce is thickened and bubbles slightly, about 5 minutes.
Bring the pot of water to a rapid boil. Add macaroni and cook 5 - 6 minutes, until barely al dente. Drain, rinse with cool water, and drain again.
While macaroni is draining, stir shredded cheese and sour cream into sauce. Taste and adjust seasonings if necessary.