Preheat your oven to 400°F and line a baking sheet with parchment paper.
In a shallow bowl, whisk the egg white until slightly frothy.
Place the panko breadcrumbs in another shallow bowl.
Dip the chicken breast first into the egg white, allowing any excess to drip off, and then coat evenly with the panko breadcrumbs.
Arrange the coated chicken on the prepared baking sheet.
Bake in the preheated oven for 20-25 minutes, or until the chicken is cooked through and the coating is golden and crispy.
While the chicken bakes, prepare the sweet and sour sauce by combining pineapple juice, rice vinegar, ketchup, cornstarch, and soy sauce in a small saucepan.
Bring the mixture to a simmer over medium heat, stirring constantly until the sauce thickens, about 3-4 minutes.
Once the chicken is done, drizzle the sweet and sour sauce over the crispy chicken or serve on the side for dipping.
Enjoy your flavorful Crispy Baked Sweet and Sour Chicken!