First of all, happy new year (maybe?)
- Steam
- Windows (or you can try using an old launcher for the game, it might not work though)
- Proton GE (I'm using 10-27)
Obs:
I'm using Arch, you might need to do some tweaking if you're using a different distro
- Download the windows version on their official website
- Run the installer with w/e program you're familiar with. For example, Lutris, Heroic, Faugus, and so on. In my case, I used Heroic to install the game.
- Just run the initial installer, it won't download anything, because it's missing some dependencies from windows, but it will create a NIKKE folder under your prefix (if you already know where the folder is supposed to be placed in your prefix, you can skip this part)
- Open your Windows OS, and install the launcher. For reference, I installed the whole game (~22gb), but you can try with just the initial client files...
- Copy the whole NIKKE directory to a USB or upload it somewhere idk
- Back to your Linux, replace the folder created by the installer with the one you just plucked from windows
- Add the game to steam and force compatibility to run with Proton GE. Also, you might have to run & cancel a few times if it doesn't open right away
Congratz, you have NIKKE running under wine!
Important: Just letting you know ahead of time, your account can be banned! I can't confirm anything yet, so do this at your own risk. Imma yolo with my main account, if I get banned f it. I have skins, but I can't be bothered to play using my phone or with a dual boot...

It might not be related. I had to reboot a couple of times yesterday, but I didn't encounter the same issue. I'm using Wayland with Hypr. Regarding the Proton version, you can also use CachyOS Proton, and both 10-27 & 10-25 are working.
I'm planning on formatting my notebook, so I will try to record a video with a step by step and update the Gist with the stuff that you sent
Edit #1:
For any1 wondering, I have been playing every single day, and it's still working! No bans so far, and the anti-cheat isn't complaining at all.