Line an 8x8 inch pan with parchment paper leaving an overhang around the sides, or line with aluminum foil and lightly grease.
In a heavy saucepan, over low heat, melt chocolate chips with 1/2 of the sweetened condensed milk, until smooth. Pour the mixture into the prepared pan, and smooth the fudge to the edges.
Repeat the process with the rest of the sweetened condensed milk and peanut butter chips. Pour and spread the mixture over top of the chocolate fudge layer.
Sprinkle the chocolate chips and lightly press them into the top of the fudge.
Place the fudge in the fridge to set for 4 hours.
Once hardened, remove from the fridge and lift the fudge out of the pan using the overhang of the parchment paper or aluminum foil.