In a small bowl, combine sugar, salt, garlic powder, and chipotle powder. Set aside.
Wash the sweet potato and dry completely. Using a mandoline, slice the sweet potato very thin.
Line a baking sheet with paper towels. Pour about 1 inch of oil in a heavy pot over medium heat. Allow the oil to reach 375°F on a deep-fry thermometer. Fry the sweet potato slices, working in batches. Cook for 2 to 3 minutes or until golden brown. Transfer the fried chips to the prepared baking sheet. Repeat the process with the rest of the slices.
Sprinkle seasoning over the chips. Transfer to a serving bowl and sprinkle additional seasoning. Serve.
Substitute smoked chipotle for smoked paprika for a less spicy seasoning.