Is B.Tech from IIT sufficient for a good and secure job?

Landing into an IIT will not secure you a lavish job. For that, you need to work harder as the competition is increasing a lot. So, you need to maintain a good CGPA and always seek for an internship if you get a chance.

B.Tech from IIT with a reasonably good performance has the high probability of you getting a good job. Nowadays secure job is a myth. Even Government or PSU jobs are no longer secure. If you work hard all jobs can be converted into secure just by your own talent and performance.

Yes, definitely. Mostly, core and corporate companies will hire the students from IIT only. Both core and corporate companies offers good salary package in IIT.