I found your question randomly and don’t know if you need an answer – but one of the main differences I can see between Nova and Chatgpt directly is that with chat gpt all content created either by you or chatgpt in your conversations is owned by you, whereas with Nova all content you submit or is generated belongs to them.

​https://www.reddit.com/r/ChatGPT/comments/125eus7/nova_app_vs_chatgpt_plus_differences/