Recovering deleted messages in Google Chat can be challenging, as there is no official way to retrieve them once they are deleted. However, there are a few steps you can try:

Check Your Email History: If your Google Chat was linked to Gmail, some conversations might have been automatically saved. Search for old messages in Gmail by using keywords related to the chat or contact.

Archived Conversations: If you archived a conversation instead of deleting it, you can find it by clicking on the "More" tab in the chat window and selecting "Archived."

Google Vault (for Workspace Users): If you are using Google Workspace and your organization uses Google Vault, an admin may be able to recover deleted chats within a certain retention period.

Data Recovery Tools: Third-party data recovery tools may offer potential solutions, but these can be unreliable and should be approached cautiously.

Unfortunately, once a Google Chat message is permanently deleted, it cannot typically be recovered. It’s advisable to archive important conversations rather than delete them to avoid accidental loss. Recover Deleted Google Chat

For more detailed guidance, visit the Google Help Center