Last year the Bears were in a somewhat similar situation, with the running game faltering early. Howard was roundly criticized for terrible production, and the consensus was that he was over the hill. Then Nagy changed the offensive game plans to play to his strengths, and he performed well, along with the team. Of course, as soon as the season ended, Howard was eliminated.
If Nagy once again changes his game plans to establish a running game, the Bears are likely to improve greatly on offense. However, I doubt that it will be enough to turn around the season.
I would have no problem with Nagy's play calling, if he had a team (quarterback and offensive line) that could handle it. But right now, he has neither, and refusing to adjust to reality is foolish.