Attach white to the Arduino's ground, red to 5 volt+, green to analog pin 4, yellow to analog pin 5. The nunchuck is only supposed to get 3.3+ volts. So far it has worked fine at 5 volts, but be warned. I am guessing that using the higher voltage will shorten the nunchucks lifespan...........Consulting the chip's data sheet (ST LIS3L02AL), it looks like this could be caused by running it at 5V instead of 3.3V. It doesn't seem to do any harm, but you might get different readings at different supply voltages.