To check potatoes for doneness, partially unwrap the largest potato, and pierce center with a fork (avoid piercing fork directly into aluminum foil). If the fork glides in easily, potatoes are done.
Wrap each potato in a piece of aluminum foil; place potatoes on a baking sheet.
Bake at 425° for 45 minutes or until potatoes are tender.
Cut potatoes in half lengthwise; carefully scoop out pulp into a large bowl, leaving shells intact. Stir together potato pulp, 1/2 cup shredded Cheddar cheese, 1/2 cup sour cream, and 1 teaspoon Buffalo-style hot sauce.
Spoon potato mixture evenly into shells; sprinkle tops evenly with remaining 1/4 cup shredded Cheddar cheese. Return potatoes to baking sheet, and bake at 425º for 5 to 6 minutes or until cheese melts.
Sprinkle chicken evenly with salt and chili powder, and cook in hot vegetable oil in a large nonstick skillet over medium-high heat 7 minutes or until chicken is browned, stirring often. Stir in 2 tablespoons white vinegar, 2 tablespoons Buffalo-style hot sauce, and 2 tablespoons light margarine; stir until sauce is blended and chicken is coated. Cook 1 minute; remove skillet from heat.
Spoon chicken mixture evenly over tops of baked potatoes. Serve with desired toppings.