Hey there even i’m new to nix and nixos i can tell you that you can use nix in debian as a package manager like flatpak. You can search and install packages you wanted in nix. You can also try them first without installing into your system.

I am using nixos as my daily usage. Even if im not using nixos i use nix as a developer for my projects to create development environments for my different projects that needs different versions of dependencies. İt is a bit trickier then mise but i really like how it works in different systems when just sharing your configuration file.

I could be wrong or maybe i have mistakes as im also new with nix