Yes. You can delete discussion posts, comments, replies, and chat messages.
To delete a message on iPhone, navigate to the message or discussion you'd like to delete. Press and long hold to the left of the message bubble. An options menu will appear with the option to edit or delete the selected message. Tap 'Delete'.
For iPad users: Tap the chat icon in the top right nav to pop out the chat panel where all your chats live.
A confirmation prompt will appear. Tap delete to confirm that the message will be deleted.