Combine milk and hot sauce in a shallow dish; add catfish. Cover and chill 8 hours, turning occasionally.
Remove catfish from milk mixture. Whisk egg into milk mixture until blended.
Combine 3/4 cup flour and next 3 ingredients; dredge catfish in flour mixture, shaking off excess. Dip in egg mixture; coat with pecans.
Pour oil to a depth of 2 inches into a Dutch oven; heat to 360°. Fry catfish 3 minutes on each side or until it flakes with a fork. Drain fish on paper towels.
Bring wine, whipping cream, and lemon juice to a boil, stirring constantly. Whisk in 1 tablespoon flour and garlic powder, and simmer, stirring often, 8 to 10 minutes or until thickened. Remove from heat; whisk in butter. Serve over fish.