I think there is no real way to know what his kid can be based on last year. the O was a complete mess. But if Nagy isn't going to use the RB much then it might never matter; and we might not ever know what he could be.
I do think he can thrive on a few plays if the OL and passing game are in place, but I doubt he ever gets a shot a 1k+ yards.
And if he never has a 1k season I'm fine with that, if he can be an effective option when he does run the ball and catch the ball - and block well as needed.