So I watched a video on Nabokov this morning (posted over a month ago, so a lot of this guys analysis was on things from the previous season). One of the biggest things he noted was that Nabokov likes to use T-cuts for the vast majority of his movements, when shuffles should be the go to. Leads to him ending up off his angles a bunch.
He made the same comment that his erratic nature at times leads to to the insane stats he has put up, but can lead to him looking bad when its not working (which will get exposed more in the NHL).
Hopefully Nabokov or the goalie coach he works with can train this out of his game.
This is an area where I could really get into the weeds.
T pushes are being heavily phased out in coaching for the exact reason you're stating. It has become an easily exploitable area and moving towards shuffles and more narrow stances is the trend (side note... I'm seeing kids training with 3/4" and 7/8" hollows. No idea how they have enough bite to push, but it really helps with their shuffles. Blows my mind I can't imagine a goalie at a 5/8" myself.). There is no getting away from the T push on bigger movements, but it should not be the primary move as goalies just aren't as exact in their positioning. Otter when he was coming up, was a big T push guy. It wasn't really until he got the AHL that they worked on getting him away from that technique and he had some struggles getting used to being more composed and relying less on the explosive push.
As a smaller goalie Nabokov needs to be more explosive to cover the net properly, so he might need more t pushes... but he's going to have to be exact and very controlled in his movements for it to be successful.
Alongside this, one of the biggest differences between big and small ice is the angles at which the goalies are exposed and where shooters come from. It seems counter intuitive, but you have a lot more variance in the angles of shots on small ice vs big ice. You don't see nearly as many below the faceoff dot shots on big ice. Now the KHL has been moving towards small ice, but there are still a lot of 92' sheets out there (this is the Finnish size). Metallurg is one of the 92' sheets. Plus the style of games dictate some changes in angles. This simply means that positioning is huge in the NA game. If you don't have it, you'll be exposed eventually.
All of this is to say, there should be the expectation of an adjustment. Nabokov has some natural disadvantages with his size and style that will have to be worked out. A guy like Frank would be ideal to teach him how to succeed in the NHL as he had to make many of the same adjustments through his career (many were made prior to him in NA, but some came here too).