gistfile1.sh

# run this as root (as root user, not with sudo)
while [ 1 ]; do echo | sudo -u nonprivilegeduser nc -l -U /tmp/reload_nginx && /etc/init.d/nginx reload; done

# or as an upstart job
script
  echo | nc -l -U /tmp/reload_nginx && /etc/init.d/nginx reload
end script
respawn

# now any process can run this or do the equivalent with sockets to trigger reload
nc -U /tmp/reload_nginx