Mix crumbs and butter. Press in pie plate. Chill until firm. Pack ice cream into crust. Freeze 1 hour.
Place oven rack in top position. Heat 450 degrees. Mix whites and salt until soft peaks form. Add marshmallow and beat until peaks are stiff and shiny. Fold in 1/2 cup of chocolate chips. Spread over ice cream quickly. Sprinkle 2 tablespoons chocolate chips. Bake 5 minutes or until meringue is lightly browned. Serve immediately or cover and freeze up to 2 weeks.