Hi
@dysan,
We've added support for the Nano!
Steps for you to try it out:
1) Make sure you have v0.0.0.10 of the Chrome app, you can check in chrome://extensions - if you have an older version the easier way to update is to restart your Chromebook
2) Once updated, plug in the Nano and click "Board at /dev/tty<something>" or "Select Other Board & Port" from the board selection dropdown in the Create Web Editor
3) Select the "Arduino Nano" (you'll have to scroll), and the desired port.