In the handbook section 13.2.1. "Preventing Logins" the path to nologin is used inconsistently: The first time the path is given as /sbin/nologin, the other two times as /usr/sbin/nologin. Looking at bug #116758 it should likely be /usr/sbin/nologin in the first instance as well.
A commit references this bug: Author: pluknet Date: Thu Jul 18 11:31:35 UTC 2019 New revision: 53262 URL: https://svnweb.freebsd.org/changeset/doc/53262 Log: Consistent use of /usr/sbin/nologin. PR: 239121 Changes: head/en_US.ISO8859-1/books/handbook/network-servers/chapter.xml head/en_US.ISO8859-1/books/handbook/security/chapter.xml
Committed, thanks.