Thanks to numerous contributions and a nice helping of determination (Bisq is a Java application after all), there is now a working Nix package for Bisq!
I still need to refactor the Nix code, but if you want to use Bisq on NixOS I encourage you to try the package and provide feedback. For what it’s worth, I successfully completed a transaction, and I’m confident enough in the package to have started another.
I look forward to hearing about your experience.
There’s now a pull request: bisq: init at 1.6.2 by emmanuelrosa · Pull Request #119038 · NixOS/nixpkgs · GitHub
Try it and report back in the PR.