This code will work when you want to move from an xib to a viewcontroller in Storyboard,Its working for me.
UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"MainStoryboard" bundle:nil];
UIViewController *vc = [storyboard instantiateViewControllerWithIdentifier:@"IDENTIFIER"];
[self.navigationController pushViewController:vc animated:YES];