1.Line two trays with baking paper.
2.Combine condensed milk and butter in large heavy-based saucepan; cook, stirring, over medium heat, about 10 minutes or until mixture is a caramel colour. Remove from heat; quickly stir in nuts, popcorn and coconut.
3.Working quickly, roll walnut-sized pieces of mixture into balls. Dip balls in chocolate; place on trays. Refrigerate until firm.