In most cases, the zoom rubber grip is just a friction-fit part. You can usually peel off the old rubber ring and stretch a replacement ring into place without disassembling the lens or removing the front filter-thread ring.

If you want a DIY fix, replacement rubber grips are commonly sold online, and fitting one is essentially like installing a large rubber band. Take care not to force anything or damage adjacent parts.

If you’re unsure, or if your lens already has other issues such as loose filter threads, the safest option is to contact Nikon or a camera repair shop. They can confirm the correct part and install it properly. Avoid deeper lens disassembly unless you’re experienced, since that can easily cause more problems.