NCM & NPM each have their own database. In most cases I've seen, people are actually wanting to populate their NCM nodes list from Orion. This is possible and very easy to do during or after the configuration of NCM.
For NCM web integration into Orion NPM there is a .exe that you must run on the NPM server. This allows you to view all NCM details within the Orion web console.
Orion has a very easy to use and powerful network discovery that should help you discover and import nodes into your Orion NPM environment. Have you checked that out yet?
Hope that helps,