Why do my constraints all of a sudden break within a UINavigationController?

Question

Placing my VC normally as self.window?.rootViewController = UITableViewVC() produces the expected result.

self.window = UIWindow(frame: UIScreen.main.bounds)
self.window?.backgroundColor = UIColor.darkGray
let nvc = UINavigationController(rootViewController: UITableViewVC())
self.window?.rootViewController = UITableViewVC()

The moment I contain it inside a UINavigationController, the constraints fail me.

self.window = UIWindow(frame: UIScreen.main.bounds)
self.window?.backgroundColor = UIColor.darkGray
let nvc = UINavigationController(rootViewController: UITableViewVC())
self.window?.rootViewController = nvc

I don't understand what the UINVC did all of a sudden that my VC doesn't display properly.

Here is how I set them up with SnapKit.

class UITableViewVC: UIViewController, 
                     UITableViewDelegate, 
                     UITableViewDataSource {

    override func loadView() {
        self.view.addSubview(tableView)

        view.translatesAutoresizingMaskIntoConstraints = false
        tableView.translatesAutoresizingMaskIntoConstraints = false

        tableView.snp.remakeConstraints { [unowned self] (make: ConstraintMaker) in
            make.topMargin.equalTo(self.view.bounds.size.height*0.35)
            make.left.equalTo(view).offset(self.view.bounds.size.width*0.15)
            make.right.equalTo(-self.view.bounds.size.width*0.15)
            make.bottom.equalTo(view.safeAreaLayoutGuide.snp.bottom)
        }
    }