Yes, it’s quite easy to run an Omni Automation script from iOS Shortcuts. You need to open a URL of the form:
omnifocus:///omnijs-run?script=
The script parameter can be an entire complex script or just a call to one of your installed plug-in actions (URL-encoded in both cases).
The following is an old page based on the Workflow app but the techniques showed continue to apply:
https://omni-automation.com/workflow/
Since you want to pass an parameter (your note text), I recommend studying this page about the new script security mechanism and how it manages arguments to functions which you call from outside OF:
https://omni-automation.com/script-url/index.html
These older pages with some examples could also be useful:
https://omni-automation.com/shared/url-app-to-app.html
https://omni-automation.com/script-url/form-example.html
