Getting error when I load NSCollectionViewItem

Question

I am getting the following error when I tried to load NSCollectionviewItem in: collectionView(_ collectionView: NSCollectionView, itemForRepresentedObjectAt indexPath: IndexPath)

Error :

could not instantiate an NSViewController for a nib in the "CollectionViewCell" bundle because the bundle has not been loaded

I am loading CollectionViewItem from xib

Written following code in viewDidLoad

let nib = NSNib(nibNamed: "CollectionViewCell", bundle: nil)
    if #available(OSX 10.11, *) {
        self.collectionView.register(nib, forItemWithIdentifier: "CollectionViewCell")
    }



func collectionView(_ collectionView: NSCollectionView, itemForRepresentedObjectAt indexPath: IndexPath) -> NSCollectionViewItem {

        if #available(OSX 10.11, *) {

            let item = collectionView.makeItem(withIdentifier: "CollectionViewCell", for: indexPath)
            return item
        }

    return NSCollectionViewItem()
}