It may seem silly since Ron Paul is sort of seen as the Libertarian choice (even though he's not a Libertarian by any stretch), while Nader is generally "pro-government" and supports many regulatory agencies. However, "anti-elitism" is huge with supporters of Ron Paul and they are likely to find common ground with Nader when it comes to corporate power as well. In addition, Ron Paul supporters generally tend to look at both major political parties as "the bad guys" so at this point, one could argue, any third party candidate would likely gain the support of the Paul supporters (once Paul finally officially drops out).
Finally, here's a clip of Barack Obama responding to a question regarding his feelings on Nader entering the race:
UPDATE: Some of the commenters on Kos took this to mean that I whole-heartedly agree this scenario is likely to play out. As I did there, I want to clarify that I am not saying I absolutely think Paul supporters will turn to Nader. I realize they have substantial policy differences. However, they do agree on the war, and the fact that Nader is not part of either major political party and shares their "anti-elitism" attitude has the POTENTIAL (key word) to appeal to Paul backers.