Yes, it's absolutely possible to join an MSc in Nanotechnology after completing a BSc in Physics. In fact, a physics background is often considered a strong foundation for nanotechnology studies. Physics provides a crucial understanding of fundamental concepts like quantum mechanics, optics, and materials science, which are all essential in nanotechnology.
However, the specific admission requirements will vary depending on the university and the program. Some programs might require specific physics courses or a minimum GPA. You should check the individual admission requirements of the MSc Nanotechnology programs you are interested in. They usually list this information clearly on their websites.