How to apply nixpkgs patch before PR lands in channel

[OliverGeneser]

Is it possible to apply patches to nixpkgs in Snowfall Lib?

Something like:

lib.mkFlake {
      channels.nixpkgs = {
        input = inputs.nixpkgs;
        patches = [
          (inputs.fetchpatch {
            url = "https://patch-diff.githubusercontent.com/raw/NixOS/nixpkgs/pull/370304.patch";
            sha256 = lib.fakeSha256;
          })
        ];
        config.allowUnfree = true;
      };
...

Or how would I apply patches to nixpkgs before they land in the stable/unstable channel?