I'll give you TWO perspectives i.e. TECHNICAL & HONEST
TECHNICALLY, if you are lucky enough to get admission in NUST. Just go for it. It is technically # 1. Now, if you really really love CIS, PIEAS is no slouch, it's one of the best out there. In the end if you can get into FAST & UET, don't hesitate.
HONESTLY, it does NOT depend where you study from actually when you enter the pro field. Nobody usually prefers graduates of one university over another especially internationally. So it's all upto you as how much knowledge you get can out of the 4 years. If you know the job, they'll hire you without even looking into your GPA and transcripts. If you can convice 'em that you can do it and you will, they'll hire you. Still, there are some firms in Pakistan ONLY that prefer graduates of one university over crap university. Just try to get into a university with Ph.D professors (which is a standard for a reputed one, even though they teach like crap.
In the end, in your current state, I'd have gone for FAST in BE Telecom Engineering. I too graduated in the parent field of Telecom, i.e. Electrical with Communications specialization. FAST is a really nice way to go but be warned that they are NOT reputed for Telecom. NUST & UETs are specialists in Engineering. PIEAS is a specialist in MASTERS degrees. So, it all depends on your personal choice. IMO Bahria, Air, Ripha these varsities are NEW. If you CANT get admission in any older ones, then think about these new ones. Old is pure gold brothA! Hope that helps.
After that, be prepared for unforeseen consequences (lolz). i.e. professional life or MS (including GRE nightmare for US). Even if those Tehrik-e-Taaliban of Pakistan (translates to Pure sons of Abuses will lead to banes) are trying their best to piss of US and ruining our future.
Ok sorry to derail a little bit. Farewell & goodluck in starting your journey. When you get admission, let me know, I'll come personally for ragging lolz.