The installer includes CUPS and the lp suite of commands to print documents from the CLI:
[root@nixos:~]# systemctl start cups.service
[root@nixos:~]# lpadmin -p default -E -v 'ipp://printer.example.com/ipp/print' -m everywhere
[root@nixos:~]# lpadmin -d default
[root@nixos:~]# lp something.pdf
[...]