Why did Apache nomads of the great plains flee to Mexico where they raided spanish settlements?

Apache nomads did not flee to Mexico to raid Spanish settlements. The Apache were already living in the territory that is now the southwestern United States and northern Mexico when the Spanish arrived in the 16th century. They did raid Spanish settlements but this was not the reason they relocated there. Their raids can primarily be attributed to a response to Spanish encroachment on their traditional lands and resources and attempts to enslave and convert them to Christianity.