1Mix soy sauce, 1 teaspoon cornstarch, the gingerroot and garlic in medium glass or plastic bowl. Stir in chicken. Cover and refrigerate 30 minutes.
2Mix orange juice and 2 teaspoons cornstarch until cornstarch is dissolved; set aside.
3Heat 1 teaspoon of the oil in 10-inch nonstick skillet or wok over high heat. Add chicken; stir fry 4 to 6 minutes or until chicken is no longer pink in center. Remove chicken from skillet.
4Add remaining 1 teaspoon oil to skillet. Add mushrooms and carrot; stir-fry about 3 minutes or until mushrooms are tender. Stir in chicken and orange juice mixture. Heat to boiling, stirring constantly. Boil and stir about 30 seconds or until thickened. Serve over rice.