nUI is the same as any addon in that all you have to do is delete the folders from the Addon directory to completely remove it. The only complication you will run into is if you rebind buttons while using nUI on the other computer as Blizz stores Keybindings on their servers.
I would "strongly" urge you to download the nUI+ Dev version 5.03.11. It has many many improvements over the release version and is very stable. Not to mention you will be happier with it's performance over the "release" version
