Yes, just another fanciful element of this article.
In general, if you made it past 18, expectancy ranged from 40-50 years. These populations were generally in very high stress - anemia was nearly universal, once farming started stools show universal evidence of pin worms and other parasites, and so on.
For example, the book "Centuries of Decline during the Hohokam Classic Period of Pueblo Grande" shows a mean lifespan of 20.1 years at Pueblo Grande, but 40.9 years if you make it to 18. https://books.google.com/books?id=DopkDQAAQBAJ
That's not Chaco, but gives the general idea.
Is this the usual fallacy of using the life expectancy of birth as if that was the age when average adult expected to die? Because even without googling, I'm pretty sure that once someone from this civilization survived childhood, his expected age raised considerably, to 50-60 years.