it's funny how the majority of your argument here is based on me implying that native american societies have no concept of a leadership or system so i really can't say anything more about this. you're thinking that "x is not a country" is me saying "x are dumb" with your reasoning behind including incas in this which i was never even saying. i hate to say this word but great strawman.
It was a large ancient Native American city which existed in modern-day Illinois and had industry and a stratified government.
This period appears to have fostered an agricultural revolution in upper North America, as the three-fold crops of maize, beans (legumes) and gourds (squash) were developed and adapted or bred to the temperate climates of the north from their origins in Meso-America. Richter also notes that Cahokia's advanced development coincided with the development to the west of the Chaco Canyon society, which also produced large-scale works in an apparent socially stratified society.

That link was to provide evidence of the fact that large, complex Native American societies existed.
like i said above, it has nothing to do with what i was saying and i didn't imply they weren't able to be further than a tribe once again.
On what grounds?
i would say they are a nation like the many, many, MANY people will name the groups because
it fits with them well. sure the words "nation and a country" may be used differently or interchangable but weirdly enough they have a different dictionary definition. you seem to be right that cahokians to fit to the list, so i guess they are a "country" but i feel "nation" fits better for some reason.
https://www.infoplease.com/world/general-world-statistics/state-country-and-nationWhat makes an independent State or a country today?
Has internationally recognized land and borders even if border disputes exist; (they built a city so that seems to fit)
Has permanent residents; (also seems to fit)
Has sovereignty so that no other country has power over its territory; (seems okay)
Has organized economic activity that regulates foreign and domestic trade and issues money; (did cahokians have a currency according to the wikipedia article? trading existed sure so i guess it counts)
Has a transportation network for moving goods and people; (okay)
Has an education system; (the wikipedia article did not mention anything about schools or an education system)
Has recognition from other independent states (okay)
and i'm gonna eventually and obviously be a middle man (some tribes are this and some tribes are that) and say a major group of native americans (cherokee, seminoles, chickasaw and others) were not known for any stratified government, sovereignty or any other. however like what you may have said cahokians do somewhat fit to this list. so that's literally one tribe in North America out of the many, many others though.
not every native american tribe in North America has met up to what the cahokians have done to meet up as a "country" and what you were basically implying was the exact opposite. they are called nations most likely for a reason other than a country as for others.