Rendering to specific passes is not only commonplace, but also a real time saver in the long run as more can be done in composting to remain flexible.
With this in mind, Arvid Schneider shows how to set up V-Ray rendering settings to get the rendering passes needed for a composite, some using the V-Ray Extra Tex, and also shows how to put a composite together in Nuke.
This Tutorial is about setting up your render settings in VRay to get the most of its render passes system
Arvid walks through the entire process of creating render passes from V-Ray and also shows how to render to Multichannel EXR files, and how to break the Multichannel EXR files to its core passes for compositing back in Nuke.
Check out the tutorial for V-Ray to Nuke Render Passes Compositing here.