Character mistake: When Mick arrives at walkabout hotel, Nugget introduces himself to Mick as if they have never met before. Yet in the first movie, Nugget is asking how Mick is getting on in New York. It may be just a case of over familiarity by Nugget but it doesn't make a lot of sense.
Suggested correction: It's quite possible that they haven't met, but Nugget's heard about Mick, e.g. from the people in the bar, stories, etc. Having no doubt heard so much about Mick, Nugget probably feels like he knows him, at least enough to ask how he's getting on.
I think it was just a scene to introduce the audience to Nugget. I'm pretty sure that if Nugget was a regular in that bar, then he must have known Mick.