He's a notch below Poirier despite taking him to the very brink 4.5 years ago while Poirier was in his stride and Justin hadn't hit his yet?
I mean, MMA Math isn't always great, but they did both just fight Chandler and Justin did it much better and easier. They have many common opponents as well that have had varying results between them (i.e Johnson KO'd Poirier while Justin KO'd Johnson, Charles submitted Justin in round 1 vs round 3 for Poirier, etc), hence why MMA Math isn't that great, but Chandler's a good example to show their present respective abilities as it's the same style for them to reflect their strengths against: whether they can force a stand and brawl. And Justin outstruck him much easier, defended the takedowns much easier, and got hurt less.
Maybe Poirier's the better fighter still. I just wouldn't bet on it.