Miocic would walk toward Nogueira and ko him with one punch, that's it.
Noguiera was a 220 pounds heavyweight known to being a good jiu jitsu fighter with boxing, not good boxing, just boxing.
At the time no jiu jitsu fighter had boxing skills, that was the difference between Nogueira and the others, but Nogueira wasn't the most gifted athlete, stiff, slow, no power, and his boxing is pretty weak.
And even his jiu jitsu is nothing special by today standards, there are like 30 fighters in the UFC with better bjj than Nogueira.
At 220 he would not be a proper sized heavyweight.
Miocic is a 244 pounds wrestler with letal boxing, big difference.
You can't compare fighters from the early 2000 with fighters from 2017.
Whos's next, prime Randleman vs Cain Velasquez? Or maybe prime Crocop vs JDS? They all get beat up.