what course do you want to do whats ur aim to achieve
It depends on you and what you want to achieve. Nanotech(in general) deals with inorganic compunds. While. Biotech deals with organic compounds. Now it depends on you what you like to take. P.S There are two other courses which you can take. Nano-biotechnology which combines NANOtech with BIOtech. And Bio-nanotechnolgy which combines BIOtech with NANOtech. Both have their Perks and well as Downfalls. See what suits you best.