NixOS can also be installed on UEFI systems. The procedure is by and large the same as a BIOS installation, with the following changes: You should boot the live CD in UEFI mode (consult your specific hardware's documentation for instructions). You may find the rEFInd boot manager useful. Instead of fdisk, you should use gdisk to partition your disks. You will need to have a separate partition for /boot with partition code EF00, and it should be formatted as a vfat filesystem. You must set boot.loader.systemd-boot.enable to true. nixos-generate-config should do this automatically for new configurations when booted in UEFI mode. After having mounted your installation partition to /mnt, you must mount the boot partition to /mnt/boot. You may want to look at the options starting with boot.loader.efi and boot.loader.systemd-boot as well.