What do you mean it won't work? I think rider will launch without dotnet, If not then rider dependencies should be fixed to include dotnet. Otherwise, it's the same case for any other distro.
> but I don't think it belongs in version control.
Why not? In fact you should put them in vc since anyone with nix can easily build the program exactly same as on your machine.
> Should it be personally suited, with my IDE and developer tools?
You can create different nix files: e.g. in ide/default.nix you can inherit your default shell.nix and put extra dependency. You may want to skip checking this in vc though.
For a good organization of nix files look at the reflex-frp haskell project.