Hello Aspirant,

Diploma holders can apply for JEE Main to be eligible only for JEE Advance, They can not use JEE Main score for the admission in NITs or other colleges, They will be eligible to take admission in IITs only for B.tech in the first year through JEE Advance.

If you wish to get admission direct into second year then there are many colleges offer lateral entry programme (direct into second year). Some colleges takes the admission through its own entrance Exam & soem takes the admission through their state level exam.

Good Luck!