An interesting factoid - Christianity is not unwelcome but certainly is not an offical religion on any reservation. No good can come as long as the nature/great spirit veneration is the law of the land.
Too bad Jesus is the whiteman and the enemy - reservation politics needs a little christian humility and polity to make it all bearable.
My Native American ancestors on my Mother's side were baptized Catholic by French Missionaries. On my Father's side... I'm not too sure what if any religion they followed.
The Pow-Wow was at Taos and it was truly a tourist event... There were even refreshment and souvenir stands with native american craft items....