If you made this and are having some difficulty, you may need to switch the axis (Y and X) around. I followed the initial tutorial, and found that the axis on the joystick 1 at the 2 o'clock position was wrong, and the X and Y needed to be switched. There's a more reliable code remixed from this on the top of the thingiverse comments, which added in a deadzone as well.

https://pastebin.com/erhTgRBH