Which is better, IIT Delhi Textile Technology or NIT Delhi CSE (considering I have a very high interest in programming)?

Both institutes are well known for their excellent education and opportunities offered. So you can choose the branch and college on the basis of your own preferences. However, some points you might want or consider

Campus: NIT Delhi operates from a temporary campus which is located far away from the country and its permanent campus is still under construction. IIT Delhi on the other hand is a fully-fledged established Institute with a fully functioning well facilitated campus.

Placements: Although Textile Engineering has very few core job opportunities, people tend to go for non-core jobs instead to secure a high-paying job at a top company. Meanwhile, NIT Delhi being younger than IIT Delhi has fewer companies visiting campus with CS roles despite being a demanded branch.

If you are actually keen to pursue CSE, go for better Engineering colleges like NITs, DTU, NSIT, and IIIT D. In fact even at IIT Delhi, you can pursue your coding passion alongside your main branch textile and sit for IT placements. The final decision is yours to make and you can consider additional aspects like fees, location, and academics while making your decision.