In a bowl, whisk together all the ingredients for the orange chicken sauce.
1/3 cup brown sugar, 3 Tbsp rice vinegar, 1/2 cup soy sauce, 1/3 cup chicken broth, or water, 1/3 cup orange juice, 1 Tbsp orange zest, 2 Tbsp cornstarch, 4 garlic cloves, minced, 1 Tbsp fresh ginger, grated, 1 tsp red pepper flakes