This is ridiculous to claim.Tbh I find this statement baffling. Nothing about Nico doing well at LB is specific to being a left back. He’s playing well there because he’s fast, strong, reads the game well and technically gifted.
The only reason you think he should stay there is it’s the first place he’s started a run of games in a row. It’s like seeing Szobozlai do well at RB for Liverpool and assume he can only play there.
Anyway Nico keeps maintaining he’s a midfielder and Pep said this before the international break so I think it’s moot -
“I admire a lot that he's playing in a position he's never played before. He's learning, he has to improve, but with the ball he's quite good! But his position is attacking midfielder. I'm pretty sure if he played attacking midfielder for every cross he's on the penalty spot.“
All of those things are characteristics of good LBs absolutely, you are insane to suggest otherwise. His timing on tackling is also so good and bolstered with his long legs.
Frankly, he is tailor suited to LB more so than midfield in our system.
He gets to invert, bomb wide, and still get on headers and has taken loads of shots. But it also minimizes his biggest midfield weakness in ability in small spaces not being elite like Foden or Bernie.