Heat oven to 450 degrees F. Line 2 cookie sheets with wax paper.
Unroll pie crust on work surface. With pizza cutter or knife, cut into 16 rows by 16 rows to make small squares. Arrange squares in single layer on large ungreased cookie sheet. Bake 6 to 8 minutes or until light golden brown. Remove squares from pan to cooling rack. Cool completely, about 5 minutes.
In large microwavable bowl, microwave chocolate chips, shortening and peanut butter uncovered on High 1 minute to 1 minute 30 seconds, stirring once, until chips can be stirred smooth. Add pie crust squares, peanuts (or almonds or walnuts) and marshmallows: stir gently until evenly coated. Immediately drop by heaping tablespoons onto lined cookie sheets. (If mixture gets too thick, microwave on High 15 seconds; stir) Refrigerate about 15 minutes or until set. Store covered.