Talk: Full Disk Encryption
From NixOS Wiki
Right now, this is borked. Nix will throw an error when grub is explicitly enabled. And even with that option removed, it still won't boot.
aes_x86_64 kernel module seems to be gone? I'm seeing same error as in (until I remove it from boot.initrd.availableKernelModules) https://bugs.archlinux.org/task/64721