hi,

sorry to say you can not get admission in b.tech after completing diploma in mechanical engineering in any nits. svnit stands for Sardar Vallabhbhai National Institute of Technology. nits b.tech admission is only done by jee main exam score.  nits and iits has no scheme for lateral entry admission process, so there is no admission for diploma pass candidates in btech. you may apply in other state government  engineering  or private colleges.