It is possible to send temporary messages in the delta.chat?

Hi.

There are online services like: temp-mail, guerrilla-mail or nada-mail that allow you to temporarily send and receive email messages.

It would be possible something like tempmail in delta.chat? It is possible to send temporary messages in the delta.chat?

If those providers support IMAP and SMTP, then yes, you can use them for temporary accounts.
Also you can build your own temporary email provider with GitHub - deltachat/mailadm: mail account administration tool for temporary and other account creation/modification.

For temporary messages we have an feature called “Disappearing messages” though that only works when all participants of a given chat use DeltaChat.