Found the solution on: https://wiki.nixos.org/w/index.php?title=OBS_Studio

{ config, pkgs, ... }:

{
  environment.systemPackages = with pkgs; [
    obs-studio
  ];

  programs.obs-studio = {
    enable = true;
    plugins = with pkgs.obs-studio-plugins; [
      obs-backgroundremoval
      obs-shaderfilter
      obs-composite-blur
      obs-scale-to-sound
      obs-move-transition
      obs-gradient-source
    ];
  };
}