If you were to build a prototype fighter who would be the worst possible matchup for Conor, it would be Khabib.
Honestly, I am not at all going to claim to be an expert, but I did wrestle at the Varsity level....
People saying Connor dominated a "wrestler" in Alvarez are mistaken: Alvarez in no, way shape or form ever was or is at this moment a top level wrestler. I don't even think he wrestled D1a/top level club. Khabib is one of the most skilled rider (being on top on the ground) i've ever seen in my entire life. His shots are at the hip and therefore he doesn't really leave himself open to knees/kicks as much as someone who attacks lower on the leg, and he finishes his shots explosively or can easily transition into a good position like his brutal (grip/control)clinch.
If you look at the Mendes dust up Connor can be taken down and wrestled.....he isn't a world class grappler (see giving Diaz his back easily)....he does have excellent take down defense against the likes of mediocre wrestlers, but that's not Khabib.
All that being said, Khabib is not remotely close to being elite on his feet. He has good athleticism and footwork, but if he gets sloppy McChicken will murk him with those pinpoint combinations and KO him or get him in big trouble points wise.
Such an intriguing match up....it'll be a test of who can impose their style on the other.