Norris by KO. Even with a little shaky chin, don't think Cotto at 154 had the power to take advantage. And I don't believe Cotto's chin could withstand Norris' offense.
Norris by stoppage or decision if Cotto tries to survive, maybe Cotto gets to his chin, but Cotto at 154 isn't Julian Jackson or Simon Brown (I'm not counting Mullings because Norris was visibly damaged goods at that point).
I think Norris is tailor made for Cotto, who is at least as good at 154lbs as a faded Simon Brown was. At least in a one-off situation. Norris might be faster, but he got hit more and was wide open for counters. so, Cotto by KO. However, Norris was good in rematches, so I'd pick him to make adjustments, box more, and avoid getting splattered. Norris by clear decision in a second fight.
Thing about this is, Cotto never looked as good at 154 as he did at 147. Or even 140. Nor was Cotto as heavy a hitter as Brown was at 154. So, two guys that were a little chinny (Norris more so), it comes down to who can take the other guys punches better. Wlad, for example, beat many guys with better chins then his. But they could not take his power. I don't see Cotto as heavy handed at 154 as Norris. And Norris speed could have been an issue as well.
Terrible Terry size, speed and power would be too much for Cotto at 154 imo prime 4 prime. Norris by Decision or possible stoppage late.
I actually think Cotto enjoyed a bit of a resurgence once he acclimatized himself to 154lbs. Stopped Mayorga and Margarito, and acquitted himself admirably against FMJ. He lost to Trout and Ali but Trout was a southpaw slickster and the Sadam fight was when Cotto was just about done. Cotto still had good timing and accuracy, and a great jab. I'd say those attributes, more than Brown's power were the reason why he obliterated Norris the first time around. Plus, he still hit hard enough to eventually score stoppages over some durable guys at 154lbs; and Norris would probably be there to be hit, at least in the first fight. Timing beats speed, and while Norris could get to Cotto, I think Cotto's improved strength and ring IQ might allow him to weather a few rough moments and find the opening needed to drop/stop Terrible Terry. Norris's best bet would be to box and circle like he did against Simon the second time...but I don't see Norris looking to do that unless he's convinced to do so, and by the time that happens it might be too late for him to make an adjustment.
At 140 cotto looked terrible, always getting hurt, getting dropped often, he would get in great fire fights but he'd get tagged bad and react bad. Paulie also close to outworked him
This is one of those fights whereby name value you'd think it would be more even but it's not. Norris obliterates Cotto then gets himself disqualified for hitting a downed opponent.