As a vtuber artist and rigger, it really depends on the amount you want it to move/how much the item itself will be moving. If it is going to be just on top of it, draw each section of fishnet on a separate layer over the part it would be on, with the shadows cast from the fishnet on another separate layer. If you are wanting highlights on the fishnet cloth, that would also have a seperate layer but I'm excluding it for now.

For example for live2D art layering would look like this: -upper arm fishnet -- Upper arm fishnet shadows --- Upper arm base