In medium microwavable bowl, microwave butter uncovered on High 30 seconds or until melted. Add marshmallows, and microwave in additional 30-second increments, stirring until combined and marshmallow mixture is melted. Add chow mein noodles; stir until coated. Working quickly with buttered hands, form about 1/2 cup mixture into a nest. Repeat for a total of 10 nests. Let stand 15 minutes.