Which or what IPMI tool are you using, for the initial query? Total sample output? You can limit the output of course, but as a discussion point might be a good idea to show the raw output as a reference before you grep it down to specifics, just a thought.
I did a lot of engineering around IPMI, HP Lights-out (iLO), Dell iDRAC, etc., event worked with Dell years ago to rework their design to improve its enterprise level design for iDRAC, so I know what IPMI feature set and reporting presented varies from vendor to vendor. We, my team at the time, automated IPMI configuration as part of the post PXE OS load over wire solution. Was fun, getting a solution that adapted to each of the server vendors! Ah, but I digress.
I did a quick search via Google and did not find any canned NR solution or flows applicable, it was a quick search, so apparently this is a create from scratch type of thing.
You will want to be sure to protect any credentials used, NR does this, in that simple export and import of any IPMI based flows you create will not carry forward the credentials by default. So if you have or plan to use multiple NR instances, credentials for IPMI access will be an issue you will need to address as part of your overall design/implementation.
Unfortunately, now that I am retired, I don't have access to IPMI equipped hardware, so I can't assist in any direct manner. But if you provide sample output from the CLI, that may suggest a few things we could do. As I recall, HP iLO could export a 'data' file, that had the IPMI setup and such in a less than human friendly format, that was easy to parse via programmatic methods, thus convert to something we could forward to other solutions, if your applicable IPMI solution can create such? That would be a step in the right direction.
And... Just to learn about how NR works in general, suggest you read the following as well...
Review the details on the exec node, and how to design flows that loop, so that you can query each system, in turn, via a schedule, right? There is a cron like module for NR that you will want to use as well. So, your homework, if you will, is read about the following: