Yes you are eligible and you will get lateral entry in 2nd year in any engineering colleges as per their eligibility criteria

Dear Deepak

Yeah you can. Diploma Candidates who have completed their degree or in the final year of their diploma are eligible for the Jee Mains but they will not be able to take admission in any of the campus of NIT / CFTI. If you can able to qualify JEE mains then you have to appear for the JEE Advance and will be given admission as an 12th pass student.

All the best