Line a baking sheet with parchment paper.
Using black decorating icing, pipe two small dots for the eyes and four dots in a curved pattern for the mouth. With the orange decorating icing, pipe a little line between the eyes and mouth to form a nose.
Snap the pretzel sticks into ½-inch pieces.
In a microwave-safe bowl, melt the white chocolate chips in 30-second intervals. Stir between each round until smooth.
Now for the fun part! Take an Oreo, dip it into the melted white chocolate, and flip it around using a fork to make sure it's fully coated. Once covered, place it on the prepared baking sheet.
Before the white chocolate hardens, press your marshmallow snowman head toward the back of the Oreo. Then, place three mini M&Ms in front of the marshmallow for buttons and press two pretzel arms into the sides of the Oreo.
Pop your decorated Oreos in the freezer for 10 minutes to let the chocolate set.