#2 Randy Orton

According to my rankings, I have Orton and Daniel Bryan being the final two participants inside the Elimination Chamber.
I expect the Legend Killer to eliminate at least one person due to an RKO off of one of the pods, and the two most likely candidates for that are Ali and Hardy.
If he eliminates Styles or vice versa, than a potential match at WrestleMania is certainly a possibility for the two men.
But due to reports that Orton has recently shown interest in All Elite Wrestling, I wouldn't be shocked if he either wins the WWE Championship or is one of the final two participants.
WWE changed things up right before WrestleMania when they had Bray Wyatt win the WWE Championship off of John Cena right before WrestleMania 33, so it wouldn't be out of left field to do so again.
But if you look at how things have been booked, there isn't really a built in storyline to explain why Orton would win the title or challenge for it like when he was a member of the Wyatt Family.