For most processes you can pseudo-daemonize using this old Linux command-line trick:
# ((mycommand &)&)
For example:
# ((sleep 30 &)&)
# exit
Then start a new terminal window and:
# ps aux | grep sleep
Will show that sleep 30 is still running.
What you have done is started the process as a child of a child, and when you exit, the nohup command that would normally trigger the process to exit doesn't cascade down to the grand-child, leaving it as an orphan process, still running.
I prefer this "set it and forget it" approach, no need to deal with nohup, screen, tmux, I/o redirection, or any of that stuff.