It really depends on which type of nanotechnology career you would like to pursue. Both chemical and material engineering offer different specializations that could be used in the field of nanotechnology.
Chemical engineering focuses on designing and implementing chemical processes for the production and modification of chemical products such as drugs, fuels, and food. Chemical engineers often work in collaboration with materials scientists and nanotechnologists to design and develop nanoparticles for drug delivery systems and fuel cells.
Materials engineering is focused on creating, manipulating and studying the components of products and materials used in various industries and engineering disciplines. Material engineers often apply their understanding of nanotechnology to develop materials and equipment with improved performance and renewable capabilities at an atomic and molecular level.
Both chemical and material engineering are necessary when it comes to nanotechnology. Depending upon which field of nanotechnology you would like to pursue, you may find one of these career paths more advantageous than the other. It is important to note that a career in nanotechnology will likely involve elements of both materials and chemical engineering, making knowledge and understanding of both fields important.
I hope this answer helps! Good luck!