so you'll have (assuming you're adjusting to using a single luks container as discussed earlier):

/dev/nvme0n1p1 -> a fat32 partition for your esp
/dev/nvme0n1p2 -> a luks container
  lvm
    swap
    zfs for /

sudoforge: i wiped out my laptop and trying to create btrfs system. Why does nix detect my home subvolume?,

[nix-shell:~]# btrfs subvolume list /mnt
ID 257 gen 24 top level 5 path root
ID 258 gen 10 top level 5 path home
ID 259 gen 10 top level 5 path nix

[nix-shell:~]# nixos-generate-config --show-hardware-config
# Do not modify this file!  It was generated by ‘nixos-generate-config’
# and may be overwritten by future invocations.  Please make changes
# to /etc/nixos/configuration.nix instead.
{ config, lib, pkgs, modulesPath, ... }:

{
  imports =
    [ (modulesPath + "/installer/scan/not-detected.nix")
    ];

  boot.initrd.availableKernelModules = [ "xhci_pci" "nvme" "thunderbolt" "usbhid" "uas" "sd_mod" ];
  boot.initrd.kernelModules = [ "dm-snapshot" ];
  boot.kernelModules = [ "kvm-amd" ];
  boot.extraModulePackages = [ ];

  fileSystems."/" =
    { device = "/dev/mapper/cryptroot";
      fsType = "ext4";
    };

  boot.initrd.luks.devices."cryptroot".device = "/dev/disk/by-uuid/ca6a879a-b6a8-402d-a73a-8bf47982f3d6";

  fileSystems."/boot" =
    { device = "/dev/disk/by-uuid/AF16-5E1D";
      fsType = "vfat";
      options = [ "fmask=0022" "dmask=0022" ];
    };

  fileSystems."/mnt" =
    { device = "/dev/mapper/pool-root";
      fsType = "btrfs";
      options = [ "subvol=root" ];
    };

  fileSystems."/mnt/boot" =
    { device = "/dev/disk/by-uuid/534B-D397";
      fsType = "vfat";
      options = [ "fmask=0022" "dmask=0022" ];
    };

  swapDevices =
    [ { device = "/dev/mapper/pool-swap"; }
    ];

  nixpkgs.hostPlatform = lib.mkDefault "x86_64-linux";
  hardware.cpu.amd.updateMicrocode = lib.mkDefault config.hardware.enableRedistributableFirmware;
}

sudoforge: i wiped out my laptop and trying to create btrfs system. Why does nix detect my home subvolume?,

[nix-shell:~]# btrfs subvolume list /mnt
ID 257 gen 25 top level 5 path root
ID 258 gen 10 top level 5 path home
ID 259 gen 10 top level 5 path nix

[nix-shell:~]# nixos-generate-config --root /mnt --show-hardware-config
# Do not modify this file!  It was generated by ‘nixos-generate-config’
# and may be overwritten by future invocations.  Please make changes
# to /etc/nixos/configuration.nix instead.
{ config, lib, pkgs, modulesPath, ... }:

{
  imports =
    [ (modulesPath + "/installer/scan/not-detected.nix")
    ];

  boot.initrd.availableKernelModules = [ "xhci_pci" "nvme" "thunderbolt" "usbhid" "uas" "sd_mod" ];
  boot.initrd.kernelModules = [ "dm-snapshot" ];
  boot.kernelModules = [ "kvm-amd" ];
  boot.extraModulePackages = [ ];

  fileSystems."/" =
    { device = "/dev/mapper/pool-root";
      fsType = "btrfs";
      options = [ "subvol=root" ];
    };

  fileSystems."/boot" =
    { device = "/dev/disk/by-uuid/534B-D397";
      fsType = "vfat";
      options = [ "fmask=0022" "dmask=0022" ];
    };

  swapDevices =
    [ { device = "/dev/mapper/pool-swap"; }
    ];

  nixpkgs.hostPlatform = lib.mkDefault "x86_64-linux";
  hardware.cpu.amd.updateMicrocode = lib.mkDefault config.hardware.enableRedistributableFirmware;
}

This is my setup,

[nix-shell:~]# lsblk /dev/nvme1n1
NAME            MAJ:MIN RM  SIZE RO TYPE  MOUNTPOINTS
nvme1n1         259:1    0  1.8T  0 disk  
├─nvme1n1p1     259:2    0    2G  0 part  /mnt/boot
└─nvme1n1p2     259:3    0  1.8T  0 part  
  └─cryptdisk   254:3    0  1.8T  0 crypt 
    ├─pool-swap 254:4    0   98G  0 lvm   [SWAP]
    └─pool-root 254:5    0  1.7T  0 lvm   /mnt