As an autistic woman myself, yeah, I definitely get the impression that she's on the autistic spectrum. I just finished the series myself, so I'll try to keep this brief and as spoiler free as possible.
Over the course of the miniseries, she displays a number of autistic coded traits, and I found myself highly relating despite the show not explicitly confirming her as autistic. Firstly, she demonstrates a pretty narrow focus of interests. Chess is the big one obviously, but another one that comes out as the series goes on is fashion. Anything outside these interests tends to catch her off guard and more than once she doesn't really seem to understand other interests that people have.
Secondly, she seems to have difficulties in communicating. She's very blunt in how she approaches people, and often early on misses out on a lot of social cues that others would probably pick up. There's a joke early on that flies over her head entirely, and she doesn't get it until later on in the series. As the articles that Vermillion quoted and linked above notes, multiple times she compensates for this by directly observing the people around her. This is something I've done myself and do often just to ensure I'm following social "procedure." Likewise, she doesn't quite communicate herself well to others, which causes a fair bit of misunderstanding at times too.
Lastly, she does kind of indicate sensory issues over the course of the series, even ignoring her problems with addiction. She doesn't seem to do well with large crowds at times, and we see her have indications of stimming too. More than once the camerawork reinforces this, even when she's sober.
The final episode has a good example too with how she visualizes the chessboard. I'm no chess prodigy (I barely know the rules), but this is a "talent" of sorts that I've been able to use in my own field working with computers. I found it instantly relatable when it first appeared in the series. I was watching it with a friend and told him "Oh yeah, I've been able to visualize the world like that too, except without needing to take pills. It just happens when I'm very focused on something."
I don't know if the director and/or writers intended for her to be autistic coded, nor do I know what the original author might have intended as I haven't read the novel yet. However, I do know that I could emphasize with her struggles, and relate them to issues that I've dealt with in my own life. It was very refreshing, and really elevated the show for me.
While watching, I just assumed her social issues and her personality were a result of childhood trauma (pre-orphange, mom's horrendous death, orphange) and childhood addiction.
This is an interesting thread to read and reconsider my assumptions.