swift write to screen from delegate - swift

Question

I've only been working with Swift for the last month please forgive me if I missed something everyone should know. I have been tasked with creating an app that will receive an APN (Apple Push Notification) containing a the document number of a sales order that requires approval. The app will display details about the sales order and present the user with an accept or reject option. I built a proof of concept that works perfectly with the APN. When I add the APN functionality I create an instance of the ViewController and use it to get the order details. I stored the order details in a global variable that is available to both classes (delegate and ViewController). Everything works great until I try to write order details to the screen. It fails with:
"fatal error: unexpectedly found nil while unwrapping an Optional
value"
In AppDelegate.swift I set
var vc = ViewController.self
In func
application(_ application: UIApplication, didReceiveRemoteNotification userInfo: [NSObject : AnyObject], fetchCompletionHandler completionHandler:(UIBackgroundFetchResult) -> Void)
I process the APN and call
vc.init().LogonServiceLayer()
Everything works great until it tries to write to the screen. I try to write to CardNameLabel.text. I have CardNameLabel defined as
#IBOutlet weak var CardNameLabel: UILabel!
I'm certain that I must create some sort of the an initialization function/constructor for my class. I've tried something like:
required init(coder aDecoder: NSCoder!) {
super.init(coder: aDecoder)!
// Your intializations
CardNameLabel.text = String ()
}
required init() {
super.init(nibName: nil, bundle: nil)
//Do whatever you want here
CardNameLabel.text = String ()
}
This will compile but now it fails in the constructor instead of when I am trying to update the label on the screen. Please forgive me if I'm missing something really obvious but so far I haven't found a way to update the labels on the screen using the instance of my class created in the delegate module.
What am I missing?
Thank you,
Duncan