Prototype Cells in a nib instead of a storyboard

For better re-usability I want to create a table view outside of my Storyboard.

Now when I create a UITableView based ViewController with Nib in Xcode I get the default TableView in the nib file. However, I am not able in Interface Builder to add prototype cells like I am in my Storyboard.

Is it currently not possible to add prototype cells in a nib or am I missing something.

Thanks very much for any help.