[Matt Devo]

I believe it's ChromeOS. How can I confirm this as well?

Thanks

 if your Chromebox is setup to dual boot ChromeOS and Kodi, then it's likely running LibreELEC, in which case you can simply do a manual update following the instructions on their website.  If you don't care to preserve your current setup, then you can always re-run the EZ Setup Script from ChromeOS and select the dual boot option, and it will install the latest version clean.