Customer context: The customer wants to know how they can check the average waiting time for their clients until an agent replies.
Customer: How can I check the waiting time for clients until an agent replies?
Answer: Although there isn't a report for average waiting time in chats, you can check the waiting time for tickets. Set up an SLA rule in which you define the desired reply time for agents and then you can view the SLA log in Reports->Tickets->SLA log. Additionally, you can check the Reports->Performance report and enable columns "New answer avg time" and "Open answer avg time" for more information.