NIFFT is a better choice than CS/IT of private colleges both in terms of placement percentage (more than 90% placement, which is better then NITs like NIT Patna) and amount of pay pulled by the students (both mean 4.75 lpa and maximum 14 lpa for 2017–18). Moreover its a government college with extremely less fee and its own industrial brand value.

However, manufacturing is not as lucrative option because you will have to appear for GATE from Mechanical or Production so extra work will be required. However there have been people from NIFFT's manufacturing department in the past who have made it to MIT Massachusetts and have gone to become professors at IITs. Many of them have are successfull IIM alumnis leading major companies. So it's not a complete disaster.

I won't say that you shouldn't be afraid. I will advise you to look for other options. But I will also say that your future is in your hands. Although Manufacturing engineering is not a glamorous degree, some people from this department have been exceptionally successful so in my opinion it would be unfair to criticize it. It really depends upon the student instead of the branch or college in my opinion.