Stir together the white chocolate and dark chocolate in a large bowl until completely combined. Dip the front surface of a cookie into the melted chocolate mixture. Hold the dipped cookie over the bowl so the excess runs off into the bowl. Place the cookie on the parchment paper with the triangle pointing down. Add two whole pretzel twists to each upper side of the cookie to create the deer's antlers. Add two mini chocolate chips just below each pretzel for eyes, and one chocolate chip at each triangle point for a nose. Repeat with the remaining cookies and chocolate coating. Allow the cookies to stand until set, about 20 minutes.