Butter a square pan and line bottom with wax or parchment paper for easy removal. Set to the side.
Using a microwave safe bowl, combine the chocolate chips and the condensed milk. Heat on high for 1 minute. Let it sit for 30 seconds then stir to blend together. If it still hasn’t melted completely, add in 30 second intervals of microwave time. After each heating, allow for it to cool for about 30 seconds and stirring until the consistency of the fudge is smooth.