Comparing IIT Kharagpur with NIT Rourkela is a bit illogical considering the fact that IIT Kharagpur is among the top 5 engineering colleges in the country. Yes, NIT Rourkela CSE is good in terms of infrastructure and placements but it is yet to match the level of top NITs like NIT Trichy, NIT Surathkal, NIT Warangal and MNNIT Allahabad
IIT KGP is a brand in itself and is the other institute of all IITs. you shouldn't worry even if you are getting one of the least preferred branches here. This is because by working extra hard in the first year, you can easily upgrade your branch to a better one. Even if you fail to do so let me tell you that the coding culture here is very strong and even non-CS students can be seen coding.
Ultimately, I would suggest choosing IIT KGP mainly because of its high ranking, better crowd quality, IIT tag, and extensive alumni base.
If you are sincerely interested in coding, algorithms etc and you are ready to bet your career in this branch only, then NIT Rourkela is the best choice for you. This is because the CS department of NIT Rourkela is considered the best among all the NITS. The learned faculty pool combined with decent lab facilities and placements make it a good choice for CS aspirants. NIT Rourkela offers a number of opportunities to kick start your career in CS.
However, if you lack the necessary conviction and are still not very sure about your area of interest and the branch you want to choose then the safest bet would be IIT KGP. IIT Kharagpur is way ahead of NIT in every possible aspect be it placements, infrastructure, lab facilities, research culture and alumni network.
Additionally, IIT Kharagpur has a richer coding culture than NITs where coding is limited to the circuital branches and mathematics. Irrespective of their branches, IITians are generally inclined towards coding and are ready to learn programming. So even if you take the Civil Engineering branch, you are always open to involve yourself in programming activities such as the IITs coding culture . This is only possible if you are passionate enough to invest extra time and efforts apart from your main coursework. The final decision hence should be mainly based on your preferences and goals.