A nation usually refers to a country. It can also refer to a sovereign state. In both cases, the area is self-governing. State like those in the US have their own governments and can make some of their own decisions, but ultimately they answer to the federal government. Native American tribes are sovereign nations and they do not fall under the rules of the US federal government.
A state is supposed to be the same thing as a nation. The idea of the United States was originality the 13 nations combined to keep each other strong. They originality could leave at free will each having individual persistents.Meany don't know this but there is another U.S., the United States of Mexico.
A state is a territory with its own government and borders within a larger country that has a governed entity, while nation is a body of people in a particular location with a distinct government or the sovereign state.