ios – Lacking transition from first view controller to second view controller utilizing navigation controller

I need to create a navigation hierarchy the place I need to go to a SecondViewController from FirstViewController utilizing a NavigationController. The FirstViewController incorporates a button B that I intend to make use of to go to a SecondViewController. I’m using the navigation controller idea since I need to return to the FirstViewController later. I’ve carried out the next steps to realize it:

1. I’ve embedded a NavigationController right into a storyboard X containing each the FirstViewController and SecondViewController.
2. I’ve created a segue from the button B current within the FirstView (has FirstViewController related to it) to the SecondView (has SecondViewController).
3. I set the navigationViewController nvc as following after I’ve introduced the firstViewController:

nvc = UINavigationController.init(rootViewController: firstViewController)

4. In a while, when the button B will get pressed, I execute the next code to push the secondViewController onto the navigation hierarchy:

self.nvc?.pushViewController(secondViewController, animated: true)

Nonetheless, the secondView would not current itself even after pushing.

5. I’ve named the segue between the button B and secondViewController as kSegue, so I attempted to carry out the segue as an addition to see if the secondViewController presents itself or not:

self.performSegue(withIdentifier: "kSegue", sender: self)

An exception happens when each the 4th and fifth steps are carried out collectively. The exception states that I am pushing a viewController that already exists on the navigation hierarchy, however the second view nonetheless would not open even when I remark the performSegue code.

Could I ask what mistake I’m making right here?