If you look at a map of the world you can usually find a place that escaped the europeans during colonialism. your ethiopias, japans, or turkeys. There is one massive exception. The Americas. There isn't an industrialized Incan Republic, or a Chinook empire from Alaska to the Bay of California, or anything. (though in fairness i doubt it would be in N.America if the US existed) Let's fix that. With any POD you choose, make one native american tribe retain sovereignty into the modern day. make them as big as you want and as important on the world stage as you want, but they need to be sovereign over their nation state.