My personal NixOs config. Running on a 2015 Chromebook Pixel LS (Samus). Notice that the kernel needs to be downgraded for the touchpad to be recognized.

configuration.nix

{ config, pkgs, ... }:

{
  system.stateVersion = "21.05"; # don't modify this if system is updated
  imports = [ ./hardware-configuration.nix ]; # some sort of auto-generated fstabby thing :-)
  boot.kernelPackages = pkgs.linuxPackages_5_4; # Most recent supported kernel that still has working touch and sound.
  boot.loader.systemd-boot.enable = true; # use the systemd EFI boot loader
  boot.loader.efi.canTouchEfiVariables = true; # set automatically during install
  networking.hostName = "ecdicius"; # define your hostname
  networking.wireless.enable = true;  # enables wireless support via wpa_supplicant
  networking.wireless.interfaces = [ "wlp1s0" ];  # without this, wpa_supplicant gets confused about how to start after reboot
  time.timeZone = "America/Los_Angeles"; # set your time zone
  networking.useDHCP = false; # explicitly set to false because it's deprecated
  networking.interfaces.wlp1s0.useDHCP = true; # dhcp is now set on each interface explicitly
  networking.wireless.networks.adamdavislee = { psk = "MY_PASSWORD"; }; # wpa_supplicant setup for my home wifi
  sound.enable = true; # enable sound
  hardware.pulseaudio.enable = true; # enable pulseaudio
  nixpkgs.config.allowUnfree = true; # don't restrict packages to __libre__
  security.sudo.wheelNeedsPassword = false; # don't require password for sudo
  services.openssh.enable = true; # enable SSH
  services.openssh.permitRootLogin = "no"; # don't allow remote users to SSH in as root

  # setup touchpad
  services.xserver.libinput = {
    enable = true;
    touchpad.naturalScrolling = true;
    touchpad.tapping = false;
    touchpad.accelSpeed = "0.66";
  };

  # define environment variables
  environment.variables = {
   EDITOR = "kak";
  };

  # setup the gui
  services.xserver = {
    enable = true;
    windowManager.i3.enable = true;
    displayManager.autoLogin.enable = true;
    displayManager.autoLogin.user = "adamdavislee";
  };

  # setup of the main user
  users.users.adamdavislee = {
    password = "MY_PASSWORD";
    extraGroups = [ "wheel" ];
    isNormalUser = true;
  };

  # enable source code pro
  fonts.fonts = with pkgs; [
    source-code-pro
  ];

  # enable packages
  environment.systemPackages = with pkgs; [
    kakoune
    alacritty
    jdk11
    clojure
    leiningen
    kakounePlugins.rep
    parinfer-rust
    git
    steam-run
    dropbox-cli
    google-chrome
    acpi
    i3lock
    sxhkd
    maim
    xclip
    peek
    brillo
    rlwrap
    nodejs
    python3
    evtest
    p7zip
    xfce.thunar
  ];

  # customize some keyboard mappings    # to find your own scancodes to map from and keycodes to map to, do the following:
  systemd.services.remap-samus= {       # run `sudo evtest` and select the keyboard (we'll remap search/caps-lock to left control as an example)
    wantedBy = [ "multi-user.target" ]; # press search and look at the upper line "...value db" ("db" is the scancode)
    path = with pkgs; [ kbd ];          # now press any key bound to control and look at the lower line "...code 29..." (29 is the keycode)
    script = ''
      setkeycodes db 29
      setkeycodes 1d 125
      setkeycodes 9d 126
    '';
  };

  # dropbox startup daemon
  systemd.user.services.dropbox = {
    wantedBy = [ "graphical-session.target" ];
    serviceConfig = {
      ExecStart = "${pkgs.dropbox.out}/bin/dropbox";
      ExecReload = "${pkgs.coreutils.out}/bin/kill -HUP $MAINPID";
      Restart = "on-failure";
    };
  };
}