Nikon software in effect have no DAM tools.
The keywording ability is there, that's for sure, and I use both ViewNX and sometimes CaptureNX to add data into the keywording, but there is nothing that you can do with this data other than to read it back when the file is opened.
You can't search for any of the keywords using Nikon's software(which seems a ludicrous concept. They allow you to add it, but make it close to impossible to search for it.

I use IDImager for my DAM management, it reads all the keywords in all their gory detail, and searching for them all is quick and easy