Line an 8x8 square cake pan with parchment paper. Melt chocolate wafers according to package directions. Pour into parchment paper lined cake pan and smooth to distribute evenly.

Let set at room temperature until chocolate has just started to set. It will no longer be shiny. Melt white wafers and evenly pour over dark chocolate. Use a spoon or offset spatula to smooth, being careful not to dip into second layer. Sprinkle M&M's, Christmas Sprinkles, and Nonpareils. Refrigerate until firm and cut into preferred sizes.