Line an 8-inch square baking pan with lightly-greased parchment paper or non-stick foil. Set aside. Place the chocolate chips in a microwave-safe bowl. Microwave at 70 percent power for 90 seconds. If needed, microwave for additional 15 second intervals. Stir the sweetened condensed milk into the melted chocolate until smooth. Add food coloring to desired shade of green, stirring very well.

Pour the mixture into the prepared pan and place the hearts on top. For 25 pieces of fudge, make 5 rows and columns of hearts. Chill until well set, about 4 hours. Cut into squares, one heart per square. I would recommend chilling over night.