I dont think it's that simple. Niang offers more than just hitting shots. His presence on the court does help the offense.
So far this series, according to Bball reference, the Jazz offensive rating has been 130 with Niang on the court and 125 with him off. The Nuggets offensive rating only increase by 0.3 with Niang on the court.
Of course all this stuff is small sample size and there is a lot of context to everything. Morgan's on/off numbers are pretty insane for this series. My point is just that I don't think Niang has been an issue this series at all. He's playing about as well as you can realistically expect outside of hitting every 3pt shot he takes.
Like I think last game Torrey Craig scored on him going to the rim with kind of a lucky shot. Obviously Craig was emboldened by having a guy like Niang on him, but it was still overall good defense and Utah forced a shot they'd happily surrender every-time down the court, a contested floater from a guy who isnt a scorer.