How Khabib forces the wrestling exchanges will determine the outcome of the fight. In the past Gaethje has fought off takedowns and always scrambled up quickly, but he always looks incredibly winded each time he return to the feet (see Alverez and Poirier fights). He too has acknowledged that the wrestling aspect of MMA saps his gas tank, hence he avoids during his fights. If Khabib can continually chain wrestle Gaethje and draw him into deep waters, it's going to be a very shitty night for Gaethje.
That said, Khabib does his best takedowns when his opponent has his back along the cage, his wrestling is less potent in open space (see Round 3 of the McGregor fight). Gaethje will need to use his pivots to avoid getting driven to the cage when Khabib rushes in. Even better if he can keep the offensive initiative on Khabib and force him backwards, Khabib is not as strong a defensive wrestler when put on his back foot (again see Round 3 of the McGregor fight).
If you guys listen to podcasts check out Fights Gone By by Jack Slack and Heavy Hands, all hosts were former contributors on Bloody Elbow and Vice's Fightland to get a flavor of what to expect this weekend.