One issue with this name is that modern Puebloans really don’t like it as it’s a Navajo term meaning “ancient enemies” (and in contrast to other common exonyms that cause controversies like Eskimo or Iroquois, the dislike seems to be quite vivid). “Puebloans” itself is also a sketchy term as they don’t really like to be lumped together (they wanted to appear in Civ5 as separate nations instead of a single Puebloan civ). @SoullyLizzer mentioned “Chacoans” as a potential name in another thread and I’d go with it, the Chaco Canyon was the cultural center of Ancestral Puebloans so the name is least likely to piss people off.
See also my earlier post in another thread where I mentioned two additional civs there (without gameplay ideas however): New North American Civilisations concept - #19 by smiki5five
Not sure which of the three core Mississippian civs (Siouans, Muskogeans, Caddoans) I’d pick to appear in the game NGL. Combining them into Mississippians is tempting, though we might miss on some civ diversity with their different warfare traditions.