Is there a generative AI tool for product design? 

What I want: a text interface where I can explain what I want in words and see the resulting UI in a side panel. I want to provide feedback on the fly and see the changes made instantaneously.

Not exactly what you're looking for but are you aware of

Building /bright-moments - minting onchain art IRL | /purple #15 | FID 129 #magikarp

Rome, Metropolitan City of Rome Capital, Italy

Not exactly what you're looking for but are you aware of https://diagram.com/

Diagram was acquired by Figma btw, and Jordan Singer (https://twitter.com/jsngr) is now part of the team so I would expect the Diagram featureset to hit Figma in 6-10 months