Very good sign. Heller could not even manage to grasp 46% of the vote in 2012, good luck, he will need it.
B-b-but muh incumbency! Muh weak D bench!
The thing is, even if Heller barely ekes it out in 2018, he's basically destined to lose in 2024 after 8 years of Trump or with a Democratic incumbent president running for reelection. So it might be best for the GOP to triage this seat if things aren't looking good in NV.
I think IN and MO are the only seats more likely to flip. Lean/Likely D for now.