I've added all the files manually so things should be there now (though I'd recommend grabbing things from github to preserve directory structure and get all the files).
@ndiwan you can check what kind of usb interface chip your nano clone uses: look at the bottom side of your nano, there should be only one chip. If it is a ch340 you will need the drivers given by Al.
@MiKa
Hi.
oki, in case i'll add some explanation.. I'll be busy for this week but you can simply use the serial gw example from MySensors for getting started, this should work. I didn't need to create a special board in arduino for this board, so if you're using it, you'll need to install&use the mattairtech SAMD21 board definition for the pin mapping.
https://github.com/mattairtech/ArduinoCore-samd