nixpkgs/nixos/doc/manual/installation/installing-uefi.xml

<section xmlns="http://docbook.org/ns/docbook"
         xmlns:xlink="http://www.w3.org/1999/xlink"
         xmlns:xi="http://www.w3.org/2001/XInclude"
         version="5.0"
         xml:id="sec-uefi-installation">

<title>UEFI Installation</title>

<para>NixOS can also be installed on UEFI systems.  The procedure
is by and large the same as a BIOS installation, with the following
changes:

<itemizedlist>
  <listitem>
    <para>You should boot the live CD in UEFI mode (consult your
    specific hardware's documentation for instructions). You may find
    the <link
    xlink:href="http://www.rodsbooks.com/refind">rEFInd
    boot manager</link> useful.</para>
  </listitem>
  <listitem>
    <para>Instead of <command>fdisk</command>, you should use
    <command>gdisk</command> to partition your disks. You will need to
    have a separate partition for <filename>/boot</filename> with
    partition code EF00, and it should be formatted as a
    <literal>vfat</literal> filesystem.</para>
  </listitem>
  <listitem>
    <para>You must set <option>boot.loader.systemd-boot.enable</option> to
    <literal>true</literal>. <command>nixos-generate-config</command>
    should do this automatically for new configurations when booted in
    UEFI mode.</para>
  </listitem>
  <listitem>
    <para>After having mounted your installation partition to
    <code>/mnt</code>, you must mount the <code>boot</code> partition
    to <code>/mnt/boot</code>.</para>
  </listitem>
  <listitem>
    <para>You may want to look at the options starting with
    <option>boot.loader.efi</option> and <option>boot.loader.systemd-boot</option>
    as well.</para>
  </listitem>
</itemizedlist>
</para>

</section>