The mental side is a big part of it. But there are also some real skills Nika has yet to show. I realize this is an unfair comparison, but think about all the ways Paige or Azzi (or Christyn) have of finishing at the rim -- the floats, finger rolls, baby hooks, reverses, pop-ups, side-arms, all the ways they know to use their bodies to seal off a defender, to generate contact, to force a foul. Nika has not demonstrated any of this. She doesn't have to develop a full arsenal. But there's definitely skills to work on, and the good news is that practicing skills like these is the main way to develop the mental side.
That is not a fair expectation for Nika. The reason why Paige, Azzi, and Christyn were each the #1 guard in their high school class is because they have those (and other) offensive skills. Nika is good, but is not that gifted.
I think a good comparison for Nika is Kia Nurse (as well as Kelly Faris). All of them increased their offensive productivity, and the variety of ways in which they could score, while they were at UConn. Nika has done some of that in two years, and I expect that to continue, particularly with a mid-range pull-up jumper.
My biggest concern about Nika is at the defensive end. Neither she nor Paige/Azzi are really able to defend fast guards like Aari McDonald or Henderson of South Carolina. Fortunately both of those are now in the W, but I'm sure there are other guards with a similar game in college this year. Nika doesn't have to be as quick-footed as they are to defend them effectively (see Katie Douglas in her WNBA years), but she does have to be positionally sound and aware of the scout on each player, so that she can run the player into her help defense. If she can learn to do that in the upcoming season, she will certainly be in the same league as Kia or Kelly as a UConn contributor.
Meanwhile, I'm looking forward to a healthy Aubrey, fully recovered and highly motivated at the defensive end, to be the shut-down defender against those quick penetrating guards. She is the only one on the 2022-23 roster with the athletic skill to do that. I hope she recognizes that this is a role which she can seize, and earn a lot of minutes that way.