@fullcotonalchimist You should be able to load extensions (addons, plug-ins) from the Chrome Store.
There are a couple of "ChatGPT" addons in the Opera store, but visiting the Chrome webstore will give you the option to install them in Opera.
https://chrome.google.com/webstore/category/extensions
This is the first one I found.
https://chrome.google.com/webstore/detail/openai-chatgpt-for-google/
Do be careful, as everybody is jumping on the "hey! Here's a plugin!" bandwagon, and some just act as keystroke repeaters - you don't know where you data is actually going, and you may be creating accounts that other people can spy on, or take over.