Not sure how reliable it is but 538's fundamentals part of their Nevada forecast has it as a tossup race, Rosen +0.5(
link). This isn't a perfect indicator, but if Rosen were actually a terrible candidate and was supposed to win easily then it would probably have a much larger Rosen lead in the fundamentals(for instance Bill Nelson leads by 6.9% in the fundamentals and 1.4% in adjusted polls, a 5.5% gap). By comparison the polls-fundamentals gap for Nevada is pretty insignificant, only 0.3% as Rosen leads by 0.8% in adjusted polls(given Nevada polls are crap she may actually be outperforming the fundamentals by more). Not a perfect indicator but I found it quite interesting, and I'll have a look at the gaps for other races soon.