Okay, so in the process of developing my newest app, I found that my storyboard got huge, so in an effort to clean it up some, i have divided it into mult
This is a bit late for Hawke_Pilot but it might help others.
From iOS 9.0 onwards you can create a Relationship Segue to another storyboard. This means that Tab Bar View Controllers can link to View Controllers on another storyboard without some of the mind-bending tricks seen in other answers here. :-)
However, this alone doesn't help because the recipient in the other storyboard doesn't know it's being linked to a Tab Bar View Controller and won't display the Tab Bar for editing. All you need to do once you point the Storyboard Reference to the required View Controller is select the Storyboard Reference and choose Editor->Embed In->Navigation Controller. This means that the Nav Controller knows it's linked to a Tab Bar View Controller because it's on the same storyboard and will display the Tab Bar at the bottom and allow editing of the button image and title. No code required.
Admittedly, this may not suit everyone but may work for the OP.