I am looking for some corpora containing emails or chats in Spanish.
The Grupo de Ingeniería Lingüística, part of the Universidad Nacional Autónoma de México has a WhatsApp corpus of undergraduate students. They have a paper that introduces it: http://www.aclweb.org/anthology/W18-3501.
They have their own web-based corpus management tool http://www.corpus.unam.mx/geco/ but I don't see the WhatsApp corpus on there, so you might have to reach out to them and ask for permission if you would like to use it for your research. They have an active FB page.