Combine the chicken, buttermilk, salt, sugar, and hot sauce in a sealable plastic bag and shake to combine. Refrigerate for at least 2 hours or up to 12 hours. Preheat the oven to 350°F. In a large mixing bowl, use your fingers to break up the panko bread crumbs into slightly smaller pieces (this will help create a more even coating on the chicken). Add the oil, chili powder, and garlic salt and stir to combine. Working with one piece at a time, remove the chicken from the marinade, shake off the excess liquid, then toss in the bread crumbs until thoroughly coated. Place the chicken pieces on a rack set in a rimmed non-stick baking sheet. Bake on the middle rack of the oven for about 30 minutes, until the bread crumbs are evenly browned and the chicken is cooked through.