Far more likely is that Republican chances have gotten better in Florida.
Chiles voters have a 60/20 disapprove/approve rating for Scott.
That fact doesn't exist in a vacuum: What do those same voters think about Sink?
Even if Chiles was serving as a placeholder for Scott voters, don't placeholder candidates typically have their support wane on election day as they are no longer viable? Who would be the ones that remain?
What does Chiles offer Scott voters that other 3rd party candidates don't? Pretty much just inclusion int he polling and a little name recognition