IBOutlet is nil in IBDesignable class

I have a custom view class that is supposed to just contain a label. I have an extension in each target that will provide the text that should be displayed in the view, this way I don't have recreate each controller just to have a different label and background color in it.

My custom code is:

@IBDesignable
class HomeAccentView: UIView {

    @IBOutlet weak var nameLabel: UILabel!

    override init(frame: CGRect) {
        super.init(frame: frame)

        setup()
    }

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)

        setup()
    }

    override func awakeFromNib() {
        super.awakeFromNib()

        setup()
    }

    override func prepareForInterfaceBuilder() {
        super.prepareForInterfaceBuilder()

        setup()
    }

    private func setup() {
        backgroundColor = UIColor.main

        nameLabel.text = String.headerText
        nameLabel.textColor = UIColor.white
    }
}

I have my nib's file owner as HomeAccentView and the label is connected as an outlet on the storyboard.

But whenever I try to set the text of the label it's always nil. What am I missing or doing wrong?