In a microwave-safe bowl, combine your green candy melts and heat them on high for about 1 minute. Then continue melting in 15-second bursts at 50% power until completely smooth.

Stir in the sweetened condensed milk and the creme de menthe liquor or syrup until fully blended, forming a rich mixture.

Cover the bowl with plastic wrap and cool while thickening, stirring every 5 minutes until it reaches a frosting-like consistency.

Transfer the thickened fudge to a piping bag fitted with a star tip and pipe tree shapes on a lined baking sheet.

Decorate each tree with rainbow nonpareils and place a gold star sprinkle on top for a festive touch.