I have Nevada as a tossup for two reasons: the Ds dont have any candidates yet and the strength of incumbency. Once a decent D like Titus enters the race, it'll become Tilt/Lean D in my eyes
The incumbency is one reason why I have this as likely D.
Maybe one of the new congresspeople could make the immediate jump a-la Patrick Murphy (not that Murphy is exactly one you want to copy).
Likely D? Heller, as of now, has no tough competition. In addition, he won his first Senate election by one point when Obama won the state by 6. That's worth something.