Check if the cell is being registered with self.collectionView.registerClass(cellClass: AnyClass?, forCellWithReuseIdentifier identifier: String). If so, then remove that line of code.
See this answer for more info:
Why is UICollectionViewCell's outlet nil?
"If you are using a storyboard you don't want to call this. It will overwrite what you have in your storyboard."
