Oven-Fried Chicken with Waffles and White Gravy

Name: Oven-Fried Chicken with Waffles and White Gravy
Prep time: 30 min
Cook time: 30 min
Total time: 1 h
Cuisine: Southern
Ingredients: 1 large boneless, skinless, chicken breast, sliced in half lengthwise; 3 tablespoons mayonnaise; 1 cup salt and pepper kettle-cooked potato chips, finely crushed; 1 large egg white; 2 tablespoons granulated sugar, divided; 1 and 1/4 cups all-purpose flour; 1 and 1/2 teaspoons baking powder; 1/4 teaspoon baking soda; 1/4 teaspoon salt; 2 tablespoons unsalted butter, melted; 3/4 cup plus 2 tablespoons buttermilk; 2 tablespoons unsalted butter; 2 tablespoons all-purpose flour; 1/2 cup plus 2 tablespoons whole milk; 1/4 teaspoon salt; 1/4 teaspoon black pepper; 2 tablespoons scallions, chopped, optional