Automatic Execution of Python Script upon PYNQ bootup

This isn’t specific to PYNQ. The PYNQ image is based on Ubuntu.
You can web search for solutions on how to do this on Ubuntu. e.g. this should work:
https://websofttechs.com/tutorials/how-to-setup-python-script-autorun-in-ubuntu-18-04/

For reference, if you want to do this at boot:

Cathal