Preheat the oven to 350°F (175°C). Line a cookie sheet with parchment paper.
In a large bowl, cream together the powdered sugar, butter, and vanilla extract until smooth and creamy.
Add the flour, cocoa powder, salt, and chopped nuts to the creamed mixture. Mix until a cookie dough forms.
Stir in the mini chocolate chips or finely chopped chocolate.
Cover the dough with plastic wrap and refrigerate for 30 minutes.
Scoop 1 tablespoon-sized balls of dough and place them on the prepared cookie sheet, spacing them slightly apart.
Bake the cookies for 7-10 minutes, or until the bottoms are just slightly browned and the tops are no longer glossy.
Allow the cookies to stand on the cookie sheet for 2-3 minutes, then gently roll each one in powdered sugar.
Let the cookies cool completely, then roll them again in powdered sugar for a snowy finish.
Store cookies loosely covered at room temperature.