Novelettes are kind of a kludgy category, squished in between short story and novella. It's really a long-ish story (the official definition is between 7500 and 17,500 words). They do have a bit more room for characterization and worldbuilding. All of this year's nominees are available online, with the exception of Ted Chiang's "Omphalos," which is found in his short story collection Exhalation.
"The Blur in the Corner of Your Eye," Sarah Pinsker
Normally I like Pinsker's stories, but I didn't care for this one at all. I think it was because of how cavalier the writer's assistant was about her...condition. I mean, she's just been enabling this alien creature inside the writer for who knows how many years, following it when it emerges from the writer's sleeping body and scraping the eggs from the people it kills (only one in five)? Really? That's like being touchy-feely with a facehugger.
Knocking On the Door
"Omphalos," Ted Chiang
It may be blasphemy to even assign Chiang this rating, as he's been an awards favorite for decades. He's made his stellar reputation entirely on his infrequently-published stories. That said, he strikes me as sometimes caring more about his ideas and thought experiments than his characters. Not that he can't write good characterization: "The Lifecycle of Software Objects" and "The Great Silence" (the latter of which made the room get very dusty when I read it) proves otherwise. This story follows the other pattern: the idea is great, the characters...less so.
"The Archronology of Love," Caroline M. Yoachim
The first line of this story sums it up: "This is a love story, the last of a series of moments when we meet." It also involves aliens, nanites, and a layered time repository like an archaeological dig. I liked it, but it wasn't outstanding.
We Have a Winnah!
"Emergency Skin," N.K. Jemisin
This is a story only N.K. Jemisin could write--a post-apocalyptic scenario where the planet improved once the white supremacists/1% abandoned Earth to climate change and stormed off to a colony world in a huff; where the people took back control, destroyed capitalism, and instituted a utopia that restored the planet; and when a descendant of the selfish parasites who left returns to Earth to get the cell cultures needed to keep his society alive, he discovers a thriving society which is a complete antithesis to the one he came from. As she tends to do, Jemisin is playing with point of view in this story. You have to read it more than once to grasp its layers and nuances.
"Away With the Wolves," Sarah Gailey
I nominated this. It appeared in last year's special edition of Uncanny Magazine, Disabled People Destroy Fantasy. This is the story of a female werewolf who becomes a wolf not because she is unable to control herself or because she is forced to change every month, but because her lupine body frees her from the chronic pain she suffers in her human form. It's a story of choice, of paying a price to live the life you want.
"For He Can Creep," Siobhan Carroll
If I had read this in time, I would have nominated it too. This is a marvelous story, taking a real-life poet and a poem written in the eighteen century and spinning up an entire world out of it. I would love more stories about these characters, especially the Nighthunter Moppet.
I said I'm not going to rank anything yet, and I'm not, but this category will be easier to decide than others, I think.