Complex sentence: The Guachichil, Cuauchichil, or Quauhchichitl, were an Indigenous peoples that occupied the most extensive territory of all the indigenous Chichimeca Nations tribes in pre-Columbian Central Mexico.
Split into simpler sentences: The Guachichil, Cuauchichil, or Quauhchichitl, are an Indigenous peoples. Pre-contact they occupied the most extensive territory of all the indigenous Chichimeca Nations tribes in pre-Columbian Central Mexico.