Line the bottom and sides of a 13 x 9-inch pan with wax paper. Set aside.
Cook corn syrup and sugar together in a large saucepan over medium heat, stirring to dissolve sugar. Bring mixture to a boil.
Remove from the heat and using a large non-stick spoon or spatula to stir in peanut butter. Mix well.
Add cereal; stir just until lightly coated then add the chopped peanut butter cups. Mix until fully distributed and cereal is evenly coated.
Pour into the pan and pat into place.
In a microwave safe bowl, melt together the chocolate and peanut butter chips. Melt in 20 second increments stopping to stir each time. Repeat until completely smooth.
Spread evenly on top of bars.
Cool at least 45 minutes, or until firm. Cut into bars.