Heat oven to 375 degrees F. Spray baking sheet lightly with cooking spray. Cut thawed puff pastry into 24 equal-sized rectangle pieces (eg 6 rows across, 4 rows up).
Take one chunk of cheese and wrap with 2 slices of pepperoni. Top each rectangle of puff pastry with a pepperoni wrapped cheese; repeat until remaining ingredients are used. Press edges of puff pastry around filling to seal. With a pastry brush, lightly coat rolls with milk and then roll in crushed ranch-flavored potato chips. Place seam side down on large baking sheet.
Bake approximately 15 - 20 minutes or until golden brown.