PresentViewController with NavigationController

Question

We have a requirement to presentViewController with navigationcontroller with following features:

• User should be able to navigate within presented view controller and maintain a navigation stack.
• Presented View Controller with Navigation Bar should only acquire 75% of screen area.

To achieve this we presented a navigationController with new ViewController as root View Controller.

@IBAction func openModal(_ sender: Any) {
        let storyboard = UIStoryboard(name: "Main", bundle: nil)
        let pvc = storyboard.instantiateViewController(withIdentifier: "ViewControllerA") as UIViewController

        pvc.modalPresentationStyle = UIModalPresentationStyle.custom
        pvc.transitioningDelegate = self as? UIViewControllerTransitioningDelegate
        let navController = UINavigationController(rootViewController: pvc) // Creating a navigation controller with VC1 at the root of the navigation stack.
        self.present(navController, animated:true, completion: nil)
    }

 func presentationController(forPresented presented: UIViewController, presenting: UIViewController?, source: UIViewController) -> UIPresentationController? {
        return HalfSizePresentationController(presentedViewController: presented, presenting: presentingViewController)
    }

But somehow the popup appearing is not showing on half screen.

If we will present the pvc (ViewController without NavigtaionController), then it works perfectly.

self.present(pvc, animated: true, completion: nil)

Please suggest to achieve the same with navigationController.