Links work for me. Are you accessing from work, that has some web limiting policy? edit: I couldn't reach the site for a short while, but is back up again.
The nano is basically a normal u-hid, except with only 8 input/output pins (+1 a ground pin), vs the u-hid's 50 connection pins. Each of the 8 nano's pins can be individually assigned to analog joystick, joystickk button, keyboard key, mouse button, mouse axis, LED (output), or +5v (output).
Each analog axis needs one pin, plus a +5v source, which can be either another (shared) pin or an external source. Each button needs one pin, plus the (shared) ground pin. So: 2 analog axes pins, + 4 digital pins + 1 +5v pin = 7 pins. You still have at least one more free pin, and two if you get the power from somewhere else..