Line a 9x9 inch pan with foil and sprat with cooking spray. Finely crush the Nutter Butters in a food processor. Mix with melted butter in a small bowl and press into bottom of pan. Set aside.

Melt chocolate chips and sweetened condensed milk over in a saucepan over medium-low heat until melted. While this is melting, melt peanut butter chips in the microwave (be careful not to burn them). When chocolate mixture is melted, remove from heat, stir in vanilla extract, and immediately pour and spread over crust. Immediately spoon melted peanut butter chips over fudge, swirling with a knife.

Chill fudge until hardened. Cut into squares and serve.