https://github.com/ajfisher/node-pixel/blob/master/docs/johnnyfive-i2c.md
https://github.com/ajfisher/node-pixel/blob/master/docs/multipin-i2c.md
for arduino wiring diagram shows that there is no 5V connection between UNO and Nano. But from my trials it looks it is in deed needed to light up the LED strip.
imho IC2 connection will be new for many arduino users and this small error in diagram is very annoying.
I can commit a fixed image but I just wanted to confirm that it's is really an error...