The
2018 Nebula Award ballot is now available. I haven't read many but the two nominees I have read from this list are excellent.
For Best Novel:
The Calculating Stars, Mary Robinette Kowal (Tor)
For Best Novella:
Artificial Condition, Martha Wells (Tor.com Publishing)
I highly recommend both.
The Only Harmless Great Thing by Brooke Bolander, nominated for Best Novellette, was available as a Tor.com free book of the month this year so many of us may have another good option to read.