how to study btech as a Diploma holder in iit of India
If you are asking whether you can take admission in IITs in 2nd year through lateral entry then you cannot join in 2nd year in NITs/IITs.If you want to get admission in IITs in engineering then you need to appear in JEE main and qualify in it and appear in JEE advanced and get good rank.You will get admission in engineering 1st year.IITs doesn't take candidates through lateral entry.However, you can get admission in 2nd in state government/private colleges through lateral entry.You may need to appear in respective entrance exam or in some colleges the admission is based on merit in diploma.
You can refer the article below for other detailed information
https://www.google.com/amp/s/engineering.careers360.com/articles/jee-main-eligibility-criteria/amp
You can apply using the link below
https://testservices.nic.in/ExamSys/root/applyfor.aspx