B.Tech Robotics

Yes as per your marks in JEE Mains, you do have a strong chance to get admission in NIT. As you have OCB-NCL Certificate then you can easily get NITs or any other best B.Tech college.

IitB IITM IITKGP IITK NITT NITW NITS are best.

Yes, you can do it is possible.

B.Tech in robotics and automation engineering is sub branch of mechanical engineering at WPU. That means you will be studying same syllabus for 3 years as that of mechanical engineering students.The is course is new and not much is known about its faculty as it was intiated from last year. With your JEE score you have a fair chance in getting admitted in this course. So if you want to study automation and robotics you should apply for this course.
(P.S: Applications are highest for this course after cse , at least from my experience from last year.)

B.Tech robotics engineering is a four-year undergraduate programme offered by universities/colleges for specialisation in the field of robotics. Candidates successfully completing 10+2 or equivalent education in Science stream can apply for this course. B.Tech in Robotic Engineering is an interdisciplinary course. Average fee of the course is INR 70,000.

It depends on experience and skills, if you have experience in robotics no starting salary can be predicted, as because it goes to Lacs also. But, much demand in foreign countries.

Kindly visit this link:
https://www.shiksha.com/b-tech/colleges/b-tech-in-robotics-engineering-colleges-india