Which one should I choose, NIT Jalandhar for chemical or NIT Silchar in CS?

Your choice should depend on your own interests and preferences. Make the choice based on your own preferences. Consider factors like closeness to your home, Coaching/guidance for GRE and alumni network.

In my opinion, CSE in NIT Silchar is a better choice. 

Pros-

• The branch and the course itself are very popular and demanding. Will give you amazing results in the future.

• Campus placements are the best part of NIT Silchar.

• The infrastructure and facilities are top-notch

• The crowd here is qualitatively better hence the competition is also better

• Amazing extracurricular facilities 

• Silchar is well connected to major cities in India through rail and Air networks.

• The best feature of this college is its Start-up Centre which encourages entrepreneurship culture.

Cons-

• A little less developed than metropolitan cities

• You will lack the benefits of a popular title like IIT

NIT Silchar will help you realize your goals and be your constant support. Hence, rather than gaining mere tag benefits, you should focus on your career.