Line a baking sheet with parchment paper. Spread a generous 1 teaspoon peanut butter onto each of 30 crackers and then top with the remaining crackers. Place on the prepared baking sheet and refrigerate until the peanut butter is firm, 20 to 30 minutes.
Put the chocolate chips in a microwave-safe bowl and microwave on medium power in 15-second intervals, stirring, until melted, about 1 1/2 minutes. Use 2 forks to dip each sandwich into the melted chocolate until completely coated, then return to the baking sheet. (If the chocolate starts to stiffen, return it to the microwave for a few seconds.) After dipping the cookies in chocolate, decorate them with sprinkles.
Refrigerate the cookies until firm, about 30 minutes. Store in an airtight container at room temperature for up to 1 week.