Which one to choose: NSIT's ICE (instrumentation and control eng) OR IIIT UNA CSE?

Firstly, you should know that IIIT UNA is a new college and although it has the IIIT tag, it hasn't been ranked by any esteemed Ranking platforms like NIRF. Its classes are also facilitated by NIT Hamirpur's faculty and the campus and faculty are nice. 

As far as NSIT is concerned, it ranks #76 on the NIRF ranking portal for engineering and has a better location in Delhi than Hamirpur, because of the facilities and professional opportunities available. 

Here are some more pointers to help you understand better -

• If your interest lies in the program rather than the institute, then go for CSE. Although first reflect on the placement scenario of IIIT UNA, whether they receive good companies or not; if the package is satisfactory, and if speedy placements are facilitated after the course is over.
• When you take a look at NSIT, then you should know that you'd be able to build a good career as a software engineer with the ICE program, but the management will be a little difficult because of the delicate balance between coursework and developing your programming skills.
• Most ICE alumni are now pursuing MBA or working other non-technical jobs. For non-tech, NSIT offers better opportunities.

Here's a table on the placement scenario-

Lastly, decide according to your future goals and whether you'd like to pursue CSE or instrumentation.