In VPchat go to the Tools menu and select Locate. Or, click on the Locate button, which is found on the bottom right of your VPchat client.
In the Search box, type all or the beginning of the pertinent chat name.
You can choose "Exact Match" or "Case Sensitive" if you know exactly who you're looking for. Click Locate
and Matching Name(s) will appear in the Locate window.