Personally, I'd like to see Kevin Lee against Khabib.
I'd also like to see Ortega come up and fight Khabib even more so! Ortega has good stand-up, and Khabib's strength of top position plays into Ortega's strength of CRAAAAZY submissions. Plus, Ortega has a big frame, so putting on that extra weight wouldn't be too big of a problem, IMO.