Place mini paper baking cup in each of 50 mini muffin cups or place wax paper on cookie sheet.
In large microwavable bowl, microwave white chocolate uncovered on High 2 to 3 minutes, stirring every 30 seconds, until melted. Stir in condensed milk. Stir in walnuts, snack mix and coconut. Cover with plastic wrap. Let stand 15 to 20 minutes. Scoop by tablespoonfuls into muffin cups or cookie sheet. Refrigerate 2 hours.
In medium microwavable bowl, microwave bittersweet baking chocolate and shortening uncovered on High in 30-second increments until mixture can be stirred smooth. Drizzle over top of each candy drop cookie. Refrigerate until set. Store refrigerated in airtight container.