Get yourself a portable USB DVD drive. $10 to $20, depending.
Or, go here and download an earlier version of office. Requires your key.
https://www.microsoft.com/en-us/software-download/office Download Earlier Versions of Office
Alternatively, you can use a drive emulator. I have used one called Virtual CloneDrive for a number of years. It is free for home use and available on all sorts of download sites (pick one you trust that has it).
Hope this helps,
Or, you could share your dvd drive on the pc that has the drive, put your Office dvd in the drive, go to the nuc, and load office from the shared dvd drive over your local net.