Such conversions are not as easy & clearcut as converting to another video format such as avi, etc. It really depends on the quality of the converter codec. I have never tried it with nero so I can't say. I did do a trial of some ntsc to pal vids with roxio toast that worked out reasonably well. So if possible, trial it out with a DVD-RW if possible. And hoping your set top dvd player can play dvd-rw's. If you're happy with the quality then go with it.

PAL to NTSC standard format means 25 fps to 29.9x fps, 576 pixels height to 480 for ntsc. But a compressed pal file might be re-encoded at a smaller size when you receive it. If there's problems, check the audio & video synch as well. This is one of the areas such converters may go wrong.

Edit: I believe it's easier to convert from ntsc to pal than pal to ntsc. ie: less quality loss & potential side-fx.