I could nitpick the crosstabs, to Republican, to White, but the topline looks about right.
FWIW PPP has a history of leaning Republican in their Nevada polls. In 2008 their last poll had Obama winning by 4 (he won by 12) and their last poll in 2010 had Sharon Angle winning by 1 (Reid won by 6).
So does about everyone - Democrats always seem to underpoll there. It also doesn't help they are more organized than the GOP, so unless Romney's up 4-5 points there on Election Day, I don't expect him to win it.
The Reid machine, Unions and early voting. With the majority of votes in Nevada being cast over a two week span before election day it gives an organized campaign time to get their voters to the polls.