Depends which nano, and depends on what format your videos are in. have a look at the stickys they might help!
if it is ipod nano g3, just do as what you do on iPod if it is g2, you need to install ipodlinux on it.
yeh heya mate, its really simple for a nano3G! Just use any simple converter which has mp4 as an output and your set! the ipod resolution is 320x240 ~umar~
It supports, yes. But what's the point if you're not going to watch them on TV? The file is larger if it has higher resolution.