Plex Channel for viewing NextPVR content. Has the ability to stream live TV in any tuner supported by http://nextpvr.com (which is almost any BDA enabled tuner).
The Plex channel has it's own log in Plex Media Server\Logs\PMS Plugin Logs\com.plexapp.agents.nextpvr.log. This will normally be needed for any issues.
3 Options for viewing your channels in Plex: Live - Lists channels and the current show - requires a working EPG (in nextpvr) Channel List - Using a named channel group (defined in nextpvr) to list channels and ignoring the EPG. Useful for a Hauppauge Colossus. Channel Group List - lists all the channel groups and the channels for each. Whats New - New recordings
For the agent and scanner see: https://github.com/psyciknz/NPVRXML-Plex