How to easily change nixpkgs so that nixvim can build neovim against it ?

[amalgame21]

First, thanks for your tip here, I am able to build nixvim (without any modules yet) in i686-linux.
However it is inconvenient to change nixpkgs for nixvim to build.

The problem is that, the current nixpkgs cannot be used by nixivm to build neovim on i686-linux system without modification.

Since pytest-regression have some build test that is not working in i686, and neovim is depending on pytest-regression somehow, I have to disable it for neovim to build successfully like this PR does
However the PR have not merged yet so I have to do it myself.

Take my repo as example: https://github.com/amalgame21/nixvim_i686_testing/blob/main/flake.nix (This example is not working)
I patched the nixpkgs input and then pass that corresponding pkgs into makeNixvimWithModule. However it has no effect at all.
I also tried overlay with overrideAttrs which is much easier but also unsuccessful.

The only working solution for me is that I have to patch the nixpkgs prior, then point the inputs.nixpkgs.url to the nixpkgs flake that already have that patched, and then use inputs.nixvim.inputs.nixpkgs.follows = "nixpkgs" for nixvim to build against that nixpkgs. That means I have to fork the nixpkgs or clone it to local repository to do so and have to update them manually.

But why passing the pkgs into makeNixvimWithModule has no effect on building neovim?