What exactly did he do wrong?
He got done on the outside once by a fresh sub, hardly the end of the world. He even defended that situation properly by forcing the player down the outside and backing his pace and power to get a block in. Okay he got done on that instance but he got back enough to pressure the player into a rushed pass straight to one of our players. They had far more joy down our left than down our right.
It seems like unless he has a game where he isn't taken on even once, he's had a bad game, it's evidence he isn't a natural defender and we need to replace him urgently and all the good performances instantly go out the window. Perhaps some are just so used to seeing a prime Walker who was a generational freak that they cannot re-adjust.
I imagine if we stuck a prime zabaleta into this side right now, who was one of the best fullbacks around yet got done far more often than Nunes has been during his right back career so far, there would be many calling him shit too.