In addition to being a great place to look for your notes, you can also use Spotlight to locate your frequently used Siri Shortcuts for North. You can create a new note by simply tapping on your shortcut from Spotlight.
Search for your custom Siri Shortcut in Spotlight
Tap on your shortcut to launch it right there. You can enter your new note text in the input box.
Tap Done once finished writing or cancel to go back.
Once completed, Siri would you present a quick preview of your new note.