Directions: Grease 8″ x 8″ or 9″ x 9″ metal baking pan and line with plastic wrap. Set aside. In a 4 qt. saucepan, combine the chocolate and butterscotch chips, peanut butter, and butter. Cook over medium heat 2 to 3 minutes or just until ingredients are melted, stirring constantly. Remove from heat.
Stir marshmallows into the fudge mixture. Pour into the prepared pan and spread evenly. Cover with plastic wrap and refrigerate until firm, at least 3 hours. Cut into pieces and keep in an airtight container until serving time.
LINE 13 x 9-inch baking pan with foil; grease lightly.
MICROWAVE morsels and sweetened condensed milk in large, uncovered, microwave-safe bowl on HIGH (100%) power for 1 minute; STIR. Morsels may retain some of their original shape. If necessary, microwave at additional 10- to 15-second intervals, stirring just until morsels are melted. Stir in vanilla extract. Fold in marshmallows and nuts.
PRESS mixture into prepared baking pan. Refrigerate until ready to serve. Lift from pan; remove foil. Cut into pieces.