Did you check your start point in your storyboard? In other words, on the left side of your starting navigation controller, do you have the arrow pointing to it? If not, drag it until you make it point to the navigation controller.
Also, if you're doing that dynamically, have you provided your UIViewController/UITableViewController/UINavigationController Storyboard IDs? Please, double check that by clicking on your view controller in your storyboard, then in the Inspector (right side of Xcode window), go to the third tab and make sure you have set the ID and make sure they are consistent with your code.