A nano sink is a type of sink that uses nanotechnology to enhance its performance and appearance. It is made of stainless steel as a base material, but it has additional layers of coating that give it various properties. According to the web search results, some of the layers are:

An oil-free layer that prevents oil from staining the sink.
An anti-rust layer that does not allow rust to build up on the surface of the sink.
An anti-corrosion layer that allows the sink to last for years without corroding or scratching.
An anti-bacterial layer that prevents bacteria from burrowing into the porous substance of the sink.
These layers are very thin and transparent, and they are made of ceramic compounds or other nano particles. They make the sink more resistant to scratches, stains, heat, and dirt. They also make the sink easier to clean and maintain.