Having followed every election in Nevada since 2004, I can tell you that Democrats ALWAYS outrun their polls for a few reasons:
1) Many firms (especially lower-cost ones) don't poll in Spanish or poll landlines only
2) A lot of people in NV work odd hours because they work in casinos or some form of entertainment
3) The Reid Machine: possibly the one machine/GOTV operation that actually lives up to the hype, Dems have nothing else like it anywhere in the country 
As a side note on item 2): one of the coolest people I've ever met was this woman in her sixties who had worked as a blackjack dealer for over thirty years. She was exactly what you'd imagine: short hair, gravel-ey smoker's voice, didn't take sh*t from anybody.
Anyway back on topic. Yeah, I'd have to agree with most of the other posters here that NV isn't likely to be in serious play for the GOP in 2020. Could it swing to Trump? Sure. But it definitely wouldn't be the tipping point state; if the Dems are losing NV, they're getting blown out nationwide.
