It’s absolutely feasible but you’ll need to use Web API blocks rather than the built-in ChatGPT block.
It’s complicated enough that I can’t explain how to do it here but I recommend asking ChatGPT how to create a curl command or Postman settings for the API and once you have a response you like, then figure out how to convert that to blocks in Thunkable, which ChatGPT is not going to be all that helpful with.
You can see an example and discussion here: Open Ai source ChatGPT API undefined response
·····················································································································
Need help? How to Ask Great Questions 
Debugging A Project API JSON Tutorial
Want to hire a Certified Thunkable Expert? Elevate your app with Tatiang on Fiverr