Since i'd read Iowa and NH were two of Bernie's top 4 states, also since i'd never seen such as Nate's Bernie caucus edge position before, it surprised me, too. Perhaps, as a Hillary win seems as suggested a forgone Pharaoh-like result Nate is a bit bored with it all, so decided to add some spice to the race.
Dunno, lol, whatever any speculation re his reason for that 'stretch' his/their forecasting and analysis
"My point is not that the incumbent party actually has an advantage after two consecutive terms in office. (Some statistical models assume that it does, which I regard as just as questionable a claim as Ms. McArdle’s.) Instead, I’d make the more modest assertion that its odds of winning a third term are, on first approximation, 50-50." http://fivethirtyeight.blogs.nytimes.com/2013/07/18/the-white-house-is-not-a-metronome/
remains as interestingly incisive, and definitely more spot on than most. Always keeping in mind that politically on a liberal conservative divide your U.S.A is basically a 50-50 country. As is Australia.