Another issue to consider -- most nursing liability policies also cover you (provide legal representation) if you're called as a
witness (or deposed) in a lawsuit against someone else, or if you have to go before the BON for any kind of disciplinary action related to your license. The chances that one of those two things will happen during your career are
much greater than the chances that you'll be named as a defendant in a lawsuit.
Again, as TheCommuter notes, if either of those things does happen to you

, the first
hour you spend consulting with a lawyer will cost you more (out of your own pocket) than the annual premium for the liability coverage. And, once an incident has happened, you can't go out and buy insurance to cover it after the fact. There's no insurance company on earth that will sell you coverage for an event that's already happened.
I've been an RN for >20 years -- I've never worked a day without my own coverage, and I would never dream of doing so. It's the best ~$100 I spend every year ...