Line a 11 x 7 pan with parchment paper. Break off Kit Kat bars and layer them on the bottom of the pan so they cover it completely.
In a microwave safe bowl, mix together the chocolate chips and sweetened condensed milk. Microwave on high in 30 second intervals, stirring after each interval, until completely melted and smooth. Remove from microwave.
Pour the melted mixture on top of the Kit Kat's in the pan. Use a spatula to spread evenly.
Open the second package of Kit Kat candy and crush it into pieces. Sprinkle it on top of the fudge.
Chill for 3-4 hours to allow the fudge to set.
Cut into square before serving.