Actually, forever, McDonalds (along with other restaurants) is supposed to serve coffee at a "safe", although still "hot" temperature. Those two words are NOT mutually exclusive. If you haven't already, I suggest looking into the true facts of the coffee case. Let me help you...
https://www.citizen.org/article/legal-myths-the-mcdonalds-hot-coffee-case/
If you don't feel like reading, here's a video...
Now, on to the hot McNugget...
As was proven in the coffee case, something can be "hot" AND be "safe". So, my question would be was the nugget SO hot, it was unsafe to touch or eat? Did the franchise intentionally heat food hotter than what is "normal"/"safe"? The article, like most news articles, leaves a lot of facts out. What did the TESTIMONY say? I'm assuming there were experts on how hot the nuggets were supposed to be, how hot they actually were (OK, suspected they were), and then judge from there.
There's not enough information in the article posted to come to a judgement, although I'm sure some will.