In my story I have a group of androids that are able to grow in size from training and repair from damage because of the nanobots that are inside of them. Their skeleton will be made of a carbon nanotubes for the strength and weight advantage and their wiring can be nanowires for the improved conductivity.
When thinking about how their internal nanobots will get materials and because I want them to seem as human as possible I thought they could eat normal food, with their nanobots stripping carbon atoms to use in creating more bots and repairing the body, which lead me to wondering if nanomaterials can be used for every part of their body? from internal mechanisms to soft skin? otherwise food might not be a good source for getting all necessary elements. The robots will secretly charge electricity through a port so whatever is digested will only be to provide materials to the repair bots.
So my question is, in the future when nanomaterials are readily available, what other elements and materials would still be needed to make life-like androids?