Begin by placing the Green Candy Melts in a microwave-safe bowl. Heat them on high for 1 minute, then stir. If they are not fully melted, continue heating in 15-second intervals, stirring after each interval, until the mixture is smooth and glossy.

Once the candy melts are fully melted, add the sweetened condensed milk and the Creme de Menthe. Stir vigorously until all ingredients are well combined and the mixture is creamy.

Cover the mixture with plastic wrap and let it cool at room temperature, stirring every 5 minutes until it thickens to a consistency similar to thick frosting.

Prepare a piping bag with a star tip. Fill the piping bag with the fudge mixture and pipe large swirls onto parchment-lined baking sheets to form Christmas tree silhouettes.

Add a gold star sprinkle on top of each tree and generously sprinkle rainbow nonpareils on the fudge shapes for a burst of color.