Hi there, a similar question has been asked here a few times, and a couple of previous discussions may be of interest to you. This is not in any way to discourage further responses, but to get you started!

How did the Iroquois Confederacy's System of Government Influence the Constitution?

How sophisticated was the Iroquois Confederation's government at its peak?

There was this really great article I was given to read for my History theory class about this and if I remember correctly, at least as my professor argued it was more of Historical guilt? Basically Historians trying to give importance to Native Americans by tying them to something we hold highly. But really it just comes down to an idea that Historians and the public think that people like Native Americans are important and sophisticated if they influence or made things for the Western white people. So there might of some influence on the Constitution but it seems that it's more that Historians of the past stretched things to make this connection to make the Native American's important, ignoring the fact they don't need to influence white society to be important.

I will disclaim this was awhile ago and I can't remember it perfectly well and can't remember the article but I will email my professor tonight and edit and add the article when she gets back to me. I do trust her, she's got a PhD and focused on Early American history.