In bowl, whisk together hoisin sauce, soy sauce, vinegar, chili sauce, water, sugar and cornstarch. Remove 3 cups of sauce mixture and set aside. Add chicken to sauce remaining in bowl; stir together to coat chicken. Refrigerate 20 minutes.
For each serving, to order: In rondo or large sauté pan, heat oil over high heat. Add chicken; stir-fry 5 minutes or until chicken turns white. Add onions, peppers and garlic; stir-fry over medium heat about 5 minutes or until vegetables start to soften. Add reserved sauce mixture; cover and simmer 5 minutes or until sauce thickens. Add peanuts. Serve over rice.