I would say mostly elite wrestling to keep him off of you, and then decent striking.
This actually isn't a difficult skillset to find in the UFC. Triple C Cejudo, Colby Covington, Kamaru Usman, Tyron Woodley, Robert Whittaker, Yoel Romero, Jon Jones, Daniel Cormier, Stipe Miocic, etc.
All these guys have good takedown defense and good striking. For whatever reason, 155 is populated with fighters that have bad wrestling and elite striking. Poirier, Barboza, Hooker, Iaquinta, etc. None of these guys actually have good wrestling credentials.
Khabib would get mauled by a lightweight equivalent of GSP, Covington, Usman, Cejudo, etc. Because he wouldn't be able to take them down, and his striking is nowhere near good enough. He's just a lucky lucker that runs a division devoid of good wrestlers. Probably the only 155 exception is Justin Gaethje, but he's seemingly abandoned his wrestling base and would probably get taken down too.