Arduino is pretty easy, you said you have the nunchuck libraries. If you haven't done much programming before you should start simple.
Control some motors through a motor driver, start with one and make it run for 5 seconds, stop for 5 and loop.
After you can do that try to control a single motor with the nunchuck output. Each value is stored in 2 bytes so you get a number from 0 - 255 reading from teh nunchuck for the joystick, accelerometers and a true false from the buttons press. Basically have something that says:
if acc > 128 runmotor
after you can do that you can start implementing steering algorithms from different readings from the data, do some pwm speed control, make something nice.
Also you might want to do some more general programming, C is better for robotics but java, python etc will help out your programming skills which will be transferable to C when you want them. Buy a book or read online tutorials, it will help you out a lot.