They are nanobots in the sense that they rely on the biomechanical chemistry and physics. These are not tiny Robbie the Robots running around flailing arms and all like a scene out of a movie that badly crosses Fantastic Voyage with Forbidden Planet. No, these are tiny spheres that chemically attach to the surface of a virus particle and then through surfactant mechanics pull apart the outer shell spilling the virus particle contents known as the capsid.