UINavigationBar Text Color in Swift

Use NSForegroundColorAttributeName as key, not "NSForegroundColorAttributeName" string.

let titleDict: NSDictionary = [NSForegroundColorAttributeName: UIColor.whiteColor()]
self.navigationController.navigationBar.titleTextAttributes = titleDict

You can also change all UINavigationController appearances in your app within the AppDelegate.swift file. Just put the following code within the application:didFinishLaunchingWithOptions function:

var navigationBarAppearace = UINavigationBar.appearance()

navigationBarAppearace.tintColor = UIColor.YourNavigationButtonsColor()  // Back buttons and such
navigationBarAppearace.barTintColor = UIColor.YourBackgroundColor()  // Bar's background color

navigationBarAppearace.titleTextAttributes = [NSForegroundColorAttributeName:UIColor.YourTitleColor()]  // Title's text color

Creds: Coderwall's Blog Post