Hi @Mike1962,
Do you want to achieve your needs within PowerApps?
Do you want to sync files from your OneDrive to SP library at midnight each day and then delete files from OneDrive?
If you want to achieve your needs within PowerApps, I afraid that there is no way to achieve your needs currently.
I agree with @Shanescows's thought almost, I think Microsoft Flow could achieve your needs. You could consider take a try to add a Recurrence trigger within your flow, then copy files from OneDrive to SP library, after that, delete the files from your OneDrive.
I have made a test on my side, please take a try with the following workaround:

The flow works successfully as below:
More details about the OneDrive connector in Microsoft Flow, please check the following article:
OneDrive connector
Best regards,
Kris