Governors' races are rarely nationalized, news at eleven.
I'm not so sure about that. Waves definitely have strong effects on gubernatorial races. It's just that a wave doesn't always guarantee a win for the wave party. If you look at past midterm elections - especially 2006, 2010 and 2014, you can see the party that didn't control the White House winning more races than they usually did under worse circumstances.
That being said, even if November is destined to end with a 8 - 10 point D+ House PV, it wouldn't be wise to rule out a Republican win in Nevada. They did prove able to hold their own in 2006, although things have changed a lot since then, so, who knows.