Refrigerate the can of cream of coconut and mango nectar overnight. Place a large mixing bowl and beaters in the freezer for about 5 minutes before making the semifreddo.

Put the cold cream of coconut to the cold mixing bowl and add the powdered sugar. The cream of coconut will be partially solidified at the top and more watery at the bottom, this is normal as the cream part rises to the top and gets more solid. Beat on high speed until the cream of coconut gets very thick (like lightly whipped cream) add the mango nectar and mix until well blended. Spoon semifreddo into a plastic or glass container with a snug fitting lid, smooth it down to compact it and freeze for at least 8 hours or overnight.