That will work…but any edits you do in the temp catalog won’t get transferred to the main catalog which I assume you have on your main computer because those edits only exist in the temp catalog. If you’re just moving the originals to the NAS and importing them into the main catalog and don’t care about the on travel edits…that’s a fine solution. But maybe I’m misunderstanding your process.
You can also transfer the temp catalog and originals to the iMac and then open the temp catalog, find any missing originals as needed, switch to the main catalog and import the temp one and edits will be preserved…but that’s doing it the hard way. The export of temp catalog and originals into a new folder on the laptop, move that folder to the iMac and then import the exported catalog into the main catalog (either moving them during import or after import within LR to the NAS) is a cleaner, easier to not mess up solution…and I’m all over cleaner harder to mess up solutions. This is the method I use. Others put the main catalog and smart previews on an external SSD that moves between the 2 computers so ther is only 1 catalog…that works too and import on travel to a folder anyplace on the external SSD. Then back at home…within LR with the external SSD attached to the iMac…move the new originals to the NAS. Either of these systems works fine.