... actually, seriously, on second thought I think that this is bad form for Terry to go after Nipples. Sue the NBR, sure, but Nipples is just doing his job and I don't approve of suing journos personally. Their boss has all the money and told them to do it in the first place.
I would agree with you if Nipples was a bit more professional and was obviously reporting on the story in a fair and unbiased way. He isn't, however, as his Twitter posts clearly demonstrate. In fact, he probably regards being sued by Terry as some kind of badge of honour.
Most likely this is just an attempt by Terry to try and get the NBR to back-off a bit. Will probably be settled out of court, with all sides claiming to be "vindicated".
Will be an interesting one to watch though. Bob Jones did sue successfully for defamation last year, although he didn't get nearly as much as he wanted. In that case the jury found that "articles [by investment advisor Chris Lee] on his website and various other publications were motivated by ill-will towards Sir Robert".