Using XCode storyboard to instantiate view controller that uses XIB for its design
Delete the View contained by the view controller in the storyboard.
Then provide the view by configuring a nib file with the same nameas the view controller class. For example if the view controllerclass is called MyViewController, name your xib fileMyViewController.xib.
EDIT Note that Swift seed 5 started breaking this technique, because it mangles the name of the .xib file it's looking for. See my answer here for workarounds: https://stackoverflow.com/a/25539016/341994 Basically this name matching was broken in iOS 8, but then Apple repented and fixed it so that it works again in iOS 9.