Yes you can take up Btech into Nanotechnology, which has shown some immense scope.
This Specialization offers roles into Enivironmental planning as described by TERI, Nanoscienec, Thermodynamics, Molecular Technology, etc.

The stream is niche and has large scale industry application in medicine and environment studies.

There are numerous higher studies opportunities with MTech from IIsc and NIT Bhopal which are best in class for Nanotechnology.

The opportunities are hummongous in terms of salary prospects since demand for such candidates is huge.

To know about eligibility criteria check below.

https://www.google.co.in/amp/s/engineering.careers360.com/nano-technology-engineering-0%3famp

All the best..!!