In a small saucepan, combine the sugar, cornstarch and salt; stir in broth and teriyaki sauce until smooth. Cook and stir until thickened. Set aside.
In a large skillet or wok, stir-fry the snow peas, carrots, zucchini, onion, pepper and water chestnuts in oil until crisp-tender. Add the chicken, mangoes and broth mixture; heat through. Stir in plum sauce. Serve with rice. Sprinkle with almonds.