Gassing Vs Nate Diaz at that kind of pace? Expected. It's Nate Diaz. Gassing in a boxing match with that kind of pace? Expected. He's not a boxer.
For me, there are two parts to look at.
First, Max Holloway. Conor fought Max Holloway at his typical style. He didn't gas what so ever, even had plenty of grappling exchanges and takedowns in there. Didn't gas at all.
Second, Chad Mendes. While he still finished it comfortably, Conor looked very tired after getting to his feet in the second round, despite easily staying in full guard and not having to work tonnes off of his back.
These throw it up in the air for me. I feel that the Conor that faced Eddie Alvarez would have easily went the distance at that pace had he kept it standing. But when the pace is slightly out of his wheelhouse, in that he gets taken down or pushed back, I think he loses it quickly. Honestly outside of HWs I've never seen a fighter as tired as Conor against Mayweather. I think he just absolutely turns the gas tank upside down and goes for it. Maybe that's how he has a bit of success, but really I could see that strategy going against him if he fights someone with enough footwork to run away from him and frustrate him. That being said, that level of footwork against someone with the forward pressure of Conor is a massive rarity.
I think DJ would give Conor a good fight tbh. Cruz is too hittable though.