Combine soy milk, nectarine, and sugar in a blender container. Cover and blend until smooth; pour mixture into a medium bowl. Stir in sour cream. Cover and chill for 1 hour.
Pit and peel mangoes. Cut fruit into 1/2-inch cubes. For each serving, alternately layer mango pieces and sour cream mixture in a parfait glass or wine glass until glass is full, topping each serving with some sour cream mixture. If desired, garnish parfait with sliced kiwifruit, raspberries, and/or strawberries. Makes 4 servings.