The app runs fine when run on in the iphone simulator, but running it in the ipad retina simulator, I see this crash:
2015-04-15 18
Are you sure you included everything? Make sure to select all the storyboards and add to membership, in side bar, first tab.
I had this issue starting with iOS 8.3 and finally solved it yesterday. I had hoped the issue would be fixed in iOS 8.4 but it isn't so I'm assuming it isn't considered a bug.
I have a UISplitViewController with 2 UINavigationControllers as the master/detail views. The master view UINavigationController has a UITabBarController. When this was failing, there were 3 UITableViewControllers as the child views for the UITabBarController. The error was exactly what you have: iOS 8.3+ throws an error trying to load the first child view of the tab bar even though the "nib" is definitely there in the storyboard and works fine on iPhone.
The fix for me was to insert a UINavigationController between the UITabBarController and each of the UITableViewController child views. So instead of UITabBarController with "view controller" relationships to 3 UITableViewControllers, the UITabBarController now has "view controllers" relationships to 3 UINavigationControllers and each of those UINavigationControllers have "root view controller" relationships to one of the UITableViewControllers.
This may be too late but I hope it helps someone.
Are you using UISplitController? In this case I solved my issue removing the storyboard segue for master and detail and adding them programmatically