Hello,
I would be happy to help. 
The feature still exists, though has not ever been paired with the AI chatbot really.
If you navigate to the deck page for the deck in question, you should see a button that looks like the following:
Alternately, this tutorial can help walk you through the basic process: AI Smart Search - Find Flashcards with Your Files
If you’re having trouble viewing these options, for whatever reason, you might double-check the troubleshooting list here: 🤖 Why can't I see the AnkiHub AI Bot?
It may be worth noting that the AI options won’t necessarily apply to cards that you have made yourself, or cards that have been moved outside of the AnKing parent deck.
Give that a shot, let me know how you fare, and we’ll go from there and hopefully we can get you squared away.