If Trump is down 5 in NV polling, a double digit win for Biden here is definitely in the cards. NV is pretty much Safe D at this point.
Obama did win Nevada by 12% in 2008, so it's plausible. That would put Nevada in roughly the same range as Virginia and Colorado, where polls suggest that Biden is leading Trump by low double digits.
That's true. I think Biden will win CO/VA by a bit more than NV (my guess is a 12-13% win for him in those states), but I'm pretty confident that NV will trend at least slightly Democratic this year.