WiFi device fails to start after installing NixOS Flakes

Hi all,

I’ve cobbled together a repo to do a minimal install of NixOS with Flakes (see README.md & flake.nix here). I’m running into a strange issue where I can connect to WiFi using wpa_supplicant from the Minimal ISO in order to install NixOS on my machine. However, when I actually boot into the newly-installed NixOS, my WiFi network device fails to start (it times out after 1min 30s):

A start job is running for /sys/subsystem/net/devices/wlp3s0 (12s / 1min 30s)

Once I log in, the device (wlp3s0) is missing when I run ip a. For reference, I am configuring nixos-hardware here and setting up networking here (I set the commented credentials before the installation).

Any ideas? Thank you.