This document explains how to implement Data Loss Prevention scan for Chat to protect sensitive user information like SSN, Credit Card numbers etc.
The closest solution ServiceNow can suggest is Edge encryption plugin that ServiceNow provides. All the chat messages are stored in Additional Comments or Worknotes fields in chat_queue_entry table. So if the user enables pattern base edge encryption on these fields, they might be able to achieve the results. Once an encryption pattern is stored and activated, the Edge Encryption proxy server identifies strings that match the pattern in requests. Once located, the clear text string is stored in the customer's proxy database and replaced on the instance with a token. Use encryption patterns to tokenize strings that match regular patterns such as social security and credit card numbers. While we recommend that encryption configurations be the primary method of encryption, use encryption patterns as a supplement to locate and secure sensitive information found outside of encrypted fields. Please refer ServiceNow docs for more information on edge encryption.
All the available versions
Since this is a customization, ServiceNow Support will not be able to help the customer with implementing the same as ServiceNow does not offer support for implementations.