OK, y'all know I'm no expert here but I've tried the Satochip and it basically just uses Electrum, so if you've got a private key you can import it into the version of Electrum they use (which was outdated when I used my Satochip) just like any other version.  Somebody correct me if I'm wrong, but I think it's that simple.

What's not simple (or rather convenient) is having to use that card reader, but that's another story.