Panda Express' Orange Chicken is a popular dish with a secret recipe that gives it its sweet and tangy flavor. The exact ingredients and proportions used in the orange sauce are closely guarded by Panda Express. It is believed to contain a blend of orange juice, soy sauce, vinegar, sugar, and spices. The crispy chicken is coated in the flavorful orange sauce, creating a delicious combination that has made it a favorite at Panda Express.