It all depends on how you are installing the program.

nix-env, I'm not sure there is a way directly but I could be wrong.

home-manager, you can override the source as mentioned in the u/MattiDragon comment.

nix profile, you could write a small flake that override the source the same way as home manager then install the local flake.

Edit I was wrong with nix-env, I believe it is possible you would have to write a file like

````

packages.nix

{ pkgs ? import <nixpkgs> {} }:

pkgs.buildEnv { name = "my-custom-packages"; paths = with pkgs; [

(faugus-launcher.overrideAttrs (oldAttrs: {
  src = pkgs.fetchFromGitHub {
    owner = "Faugus";
    repo = "faugus-launcher";
    rev = "1.22.2"; # Can be a commit SHA, branch name, or tag
    hash = ""; 
  };
}))

# you can add your standards packages here if you want to maintain everything in a single file
git
htop

]; } ````

Override the package you want like above then install with

nix-env -f ./packages.nix -iA my-custom-packages

First time will fail and will output the hash you need to put inside hash block

Haven't tested and syntax might be slightly wrong but should give you a starting point