Nano Sketch Uploads Via USBasp/USB but wont run when powered by 12V -> 9V

Note in advance: nothing is urgent.

May we assume that your sketch runs correctly when powered over USB?

What is the 9V source? A PP3 battery? Those are quite useless in general as they can't deliver the needed current, especially if you have anything more connected than a simple button.

Your topic has been moved to a more suitable location on the forum. Installation and Troubleshooting is not for problems with (nor for advice on) your project :wink: See About the Installation & Troubleshooting category.