In a 3-quart saucepan, cook the rice in water as directed on the package. Meanwhile, in a 10-inch nonstick skillet, heat the oil over medium-high heat. Add the asparagus, mushrooms, zucchini and onion. Cook for 4 to 5 minutes or until tender. Stir in the chicken, salt and pepper. Cook until thoroughly heated, stirring occasionally. Fold the sour cream, cream cheese and mayonnaise into the hot cooked rice until blended. Fold the rice mixture into the cooked vegetable mixture. Warm through. Serve immediately.