Is there any way to make NeXuS load independently of workshelf, or to leave it working when workshelf is closed making it work somewhat like Stardock's ObjectDock?

NeXuS and WorkShelf share the same executable.

This said, provided you are running the latest Winstep Xtreme version, you can simply right click the 'NeXuS control icon -> Dock and Shelf Management -> Close Shelf' to prevent the Shelf from appearing on your screen.

If you later want it back, do the same but chose 'Open Shelf' instead.

thanx for the prompt answer, Jorge.