Instructions
Attack your opponent until his life bar is in the red.
Allow the enemy to hit you a few times to get your life bar down to about one-third. Once this happens, activate the Sharigan power by pushing the joystick on the nunchuck down and pressing the "Down" button on the Wii remote's D-pad.
Keep fighting normally until your chakra bar is full.
Get close to your opponent and push the the nunchuck joystick down to initiate the Chidori. Hold it for a few seconds until you perform the maxed-out attack.