I wanted to be able to make nix packages with purescript so I made this tool. It’s a simple CLI that generates a nix expression that can easily be imported into a flake.nix/default.nix to create your nix package. It’s written in purescript and packaged using itself. Enjoy 
(I was not aware of spago2nix before I made this. I assume it can be used to accomplish the same thing, but I have no experience with it.)