Set out the tub of Cool Whip so that it is completely thawed. Make room in the freezer so that you can set the tray in level for freezing the candy. Have the nonpareils open and ready to use.
Line an 8x8 inch square baking dish and a baking sheet or tray with parchment paper. Set these aside. (We won't be turning on the oven, though.)
Add the chocolate chips (NOT the wafers yet) to a microwave-safe bowl and heat for one minute, then stir and heat in 15- second increments, gently stirring often, until fully melted.
Remove utensils from the chocolate bowl and let the melted chocolate chips sit for about 15 minutes to come to room temperature.
Meanwhile, transfer the Cool Whip to a large bowl.
Once the chocolate has cooled, use a bowl scraper to add it to the large bowl with the Cool Whip. Gently fold to combine until there are no white streaks and it becomes a lighter-brown color.
Transfer the mixture to the prepared 8x8 square baking dish and spread it into an even layer.
Place it in the freezer for 30 to 45 minutes so it sets but still soft enough to cut.
Pick up the slab of candy by the parchment paper gently and set it on a cutting board. Using a long, sharp knife: Cut the slab into 6 rows, then 6 rows the other way, so that you have 36 small squares.
Arrange the squares on the prepared baking sheet or tray and transfer it to the freezer for 30 minutes.
Meanwhile, melt the chocolate wafers in a microwave safe bowl just like you did the chocolate chips. You can use the same bowl if you want. NOTE: Keep the candy squares in the freezer right up until you are ready to dip them into the chocoalte on the next step.
Moving quickly so the melted wafers are still warm: Dip the each square into the chocolate using forks or a candy dipping tool and set them on the prepared baking sheet or tray. Top with the nonpareils immediately, while they can stick to the warm chocolate.
Repeat until all squares are dipped and decorated. Cover and freeze until ready to serve. They can be eaten chilled or room temp, but they will get very soft if kept too long near the stove.