I'd be surprised if he could take many clean shots from Conor. Frankie can't take shots like Nate Diaz and Conor has KO'd basically everybody he's ever fought. Aldo is known for having a great chin too, got put down by a punch that Conor didn't really throw much into at all. It's not about power, land in the right spot and anybody can be put down, unless you're Nate Diaz because his chin is just ridiculous.
Frankie does have a great chin, but I'm more impressed with his ability to recover quickly. With Nate, he has a great chin to the point that basically no matter what you hit him with it doesn't do anything to him. The guy took a perfect head kick from Josh Thomson, he even leaned into it, and still didn't get put to sleep like almost everybody would. His chin is fucking ridiculous, Frankie can't take shots like that. Just because Nate did it doesn't mean Frankie will.
Now, Maynard has tons of power, but that guy can barely finish anybody. He's not Conor McGregor, not even close. Conor is one of the best finishers in MMA history, if he hurts you at all, you're done for, he's going to put you away.
I'm not saying Conor would go in and destroy Frankie, just that if Conor lands that left clean like he has on pretty much everybody, I don't see Frankie surviving it. I see him getting TKO'd, Conor won't go crazy on him like Maynard did, he'll pick his shots, mix it up nicely and put him away. He's smart with the way he finishes people, he doesn't just swarm like a mad man. That's one of the reasons he's so effective with finishing fights, because he picks his shots intelligently, creates openings and lands clean over and over.
Frankie is known for getting hurt bad and coming back to make it a close fight or win, but getting hurt like that will catch up to you. Frankie hasn't been hurt in a long time, he's improved so much in all aspects, it's especially nice to see him going back to his wrestling and not just standing so much anymore too, but like Conor said, the chin doesn't recover, it catches up to you. All great chins have been or will be cracked someday, that's just how it is. Look at Dan Henderson, Shogun Rua, Roy Nelson even got KTFO by Mark Hunt, etc, etc. Everybody can be KO'd and Frankie getting finished by Conor would not surprise me at all. He has the power and skill to do it.