TVC was not part of the ATF specification. The F-22 didn't HAVE to have it, LockMart put it in anyway to make it better. NorthGrum went for extra-stealthy and didn't.
Keep in mind that from what I've read BOTH planes satisfied the "plane" part of the ATF competition. The F-22 wasn't a "better" plane than the F-23 to any significant degree. Instead, LM won on the other parts of the competition.
In short, the USAF believed LM was more likely to deliver the F-22 as advertised, with the least troubles, and cost growth and so on. They had less confidence in NG's ability to execute the F-23 program to the same degree.
Actually, I think it safe to say that had NG been the one making the F-22 and LM the F-23 that in that case the F-23 would have won!