Preheat oven to 325°F. Lightly oil a 9x13 baking dish or coat with nonstick spray.

To make the sauce, whisk together sugar, buffalo sauce, vinegar, salt, red pepper flakes and 1 tablespoon water in a large bowl; set aside.

In a large bowl, season chicken with salt and pepper, to taste. Stir in cornstarch and gently toss to combine. Working one at a time, dip the chicken into the eggs.

Heat vegetable oil in a large saucepan. Add chicken and cook until golden brown, about 1-2 minutes. Transfer to a paper towel-lined plate; discard excess oil.

Add chicken to prepared baking dish. Top with buffalo sauce mixture. Place into oven and bake until the sauce has thickened, about 45 minutes, turning over every 15 minutes to evenly coat the chicken.

Serve immediately.