In A Large Bowl, Combine Caramel Corn, Pecans And 1 Cup Marshmallows. In A Small Heavy Saucepan, Melt Butter Over Low Heat. Add Chips And Remaining Marshmallows; Cook And Stir Until Smooth. Pour Over Caramel Corn Mixture; Toss To Coat. With Buttered Hands, Press Into A Greased 13-In. X 9-In. Pan. Cool. Cut With A Serrated Knife.