AI tools are changing constantly as are suggestions by style guides for use of and citations for them. You may wish to access the information in Chicago Manual of Style Online.
You should mention in the text that you used ChatGPT or any other AI model, but you should NOT include it in a reference or works cited section, because the material is not available to any other user.
The suggested in-text note is:
If you use the Author-Date format, the in-text citation should be:
(AI tool, Date created)
(ChatGPT, March 7, 2023)