You cannot present a viewController from within a SKScene as it is actually only being rendered on a SKView. You need a way to send a message to the SKView's viewController, which in turn will present the viewController. For this, you can use delegation or NSNotificationCenter.
Delegation
Add the following protocol definition to your SKScene's .h file:
@protocol sceneDelegate <NSObject>
-(void)showDifferentView;
@end
And declare a delegate property in the interface:
@property (weak, nonatomic) id <sceneDelegate> delegate;
Then, at the point where you want to present the share screen, use this line:
[self.delegate showDifferentView];
Now, in your viewController's .h file, implement the protocol:
@interface ViewController : UIViewController <sceneDelegate>
And, in your .m file, add the following line before you present the scene:
scene.delegate = self;
Then add the following method there:
-(void)showDifferentView
{
[self performSegueWithIdentifier:@"whateverIdentifier"];
}
NSNotificationCenter
Keep the -showDifferentView method as described in the previous alternative.
Add the viewController as a listener to the notification in it's -viewDidLoad method:
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(showDifferentView) name:@"showDifferenView" object:nil];
Then, in the scene at the point where you want to show this viewController, use this line:
[[NSNotificationCenter defaultCenter] postNotificationName:@"showDifferentView" object:nil];