Native America actually refers culturally to Northern America. There are some awesome Native American Civilizations that would be really cool. The Cherokee where an Appalachian Civilization that lived in higher classed mansions and civility than the American colonies. The Americans became jealous and turned their backs on the Cherokees who had helped them beat the Crow and other battles that would have ended Americanism altogether. The 'trail of tears' or genocidal relocation (since most people who dont want to admit genocide title their actions as: relocation) was the ultimate betrayal of the two peoples who were onced promised brotherhood and equality. Moved off their homeland for gold exploitation, ironically the reservations in Oklahoma where they were "relocated" turned out to have vast supply of oil.
Another group were the Apache Indians who dominated their territory through horror. Groups like the Anasazi, Pueblo, White Mountain, and Hopi all fell under the influence of the Apache dominace. One major military leader was Geronimo who faced the Spanish, Americans, and Mexicans and was quite successful at that.
We all know the Iroquis nation states. Two other larger influences were the Aloquin and the Mississippi nations.
Maybe a more thematic scenario might bring more appreciation as to how Native American civilizations existed and interacted. MesoAmerican Civilizations and Southern American Civilizations are culturally different than the Native American Civs as they use to have different religions and build pyramids, played different sports, etc.