XSplit Broadcaster 4.2 and above supports the use of VST3 Plugins (know more about VST3 Plugins on XSplit Broadcaster here )
Here's a list of VST3 Plugins currently known to work with XSplit Broadcaster:
If you know of other compatible VST3 Plugins that works with Broadcaster but not in the list, feel free to contact Support so we can test and add them for you.