Line 8×8 or 9×9 baking dish with foil, then spray foil with Nonstick Cooking Spray. {allow a little extra foil on the sides, so the fudge can easily be lifted out later}
In large microwave safe bowl, combine chocolate chips and sweetened condensed milk.
Microwave for 1 minute, then stir.
Microwave for an additional 45 seconds, and stir until melted. {or microwave an additional 45 seconds if needed}.
Once melted, quickly transfer to foil lined baking dish and spread out evenly. {the fudge likes to set fast, so no dilly-dallying on this part}
Sprinkle top of mixture in pan evenly with approx. 1/2 cup Butterfinger baking bits.
Transfer to refrigerator, and chill for approx. 2 hours, or until set.