Line a baking sheet or tray with parchment paper or wax paper. Set all cookies, candy eyes, icing, and a dipping utensil near your work surface so the decorations can be added while the chocolate is soft.

Melt the chocolate wafers or candy melts according to the package directions, stirring until smooth. If the coating seems too thick for dipping, stir in a small amount of the optional vegetable shortening until it becomes fluid.

Dip each Nutter Butter cookie into the melted chocolate, coating it completely or covering approximately two-thirds of the cookie. Hold it above the bowl for a moment so excess chocolate drips back into the bowl.

Place each coated cookie on the lined tray with the chocolate side facing up. Work in small batches so the surface remains soft enough for the eyes and icing.

Press two candy eyes onto each cookie before the chocolate begins to set. Add a black icing mouth and several short, uneven lines across the chocolate to suggest Chewbacca's furry face.

Add small white icing details if desired, then allow the cookies to set at room temperature or refrigerate them briefly until the chocolate is firm. Serve once the coating has hardened.