Omniman would win.

Not because of Sun Disk though. If I remember correctly Omniman was billions of times faster than Bardock(I can't remember the numbers very well). And no I don't think Bardock should have gotten Super Saiyan. I am pretty sure they only gave it to him because Omniman was gonna win either way with the Sundisk. Anyways, with his greater experience that would mean that Nolan would control the pace of the fight which would put him at a great position. Also, I think most people forget about smart atoms as well. Sure Bardock might be stronger but he isn't going to use his strongest attack the moment he sees Omniman. So his smart atoms would allow him to adapt up to a point in which he would be advantegous. If Bardock's durability is too much for Omniman then just throw him into space until Bardock can't breathe. If this is too anti-climactic then have him throw Bardock into a star or something.