This is a great and common question we get since launching our Authorizing Selling program.
At the moment, Stripe Balances and Nifty/Gemini Balances cannot be transferred between each other.
The fundamental reason being that Stripe Balances are never dormant. From the moment the proceeds of your Nifty Sale are sent to your Stripe Balance, they're en route to the account you have on file with Stripe, which you can see by going here and choosing Open Dashboard.
Frequently Asked Follow - Up: