NPTEL (National Programme on Technology Enhanced Learning), is a joint venture of the IITs and IISc, funded by the Ministry of Education (MoE) Government of India. It was launched in 2003. It started as a project to take quality education to all corners of the country, NPTEL now offers close to 600+ courses for certification every semester in about 22 disciplines.
Now coming to the question. You can use NPTEL and other online courses to brush up on a subject or for an introduction to a subject. But frankly, just doing NPTEL and other online courses may not get a job, although these may add to your skillset and knowledge. So, dont bank on these courses to help you get a job or a promotion or admissions in different or same majors. Use these courses to enhance your knowledge and practice more so that you are better at your work.