Generaly when direct coating on tools are not possible we can go for nano composite coating where the matrix may be a adhesive one and nano particles are well incorporated.
When yiu go for direct coating is possible as CVD or PVD process then you may say that nanomaterial coating.... Depends on application and process the words vary.
Nanomaterial is a general term and nanocomposite is one of the types of it.Nanocomposite is a biphasic material containing a matrix and a reinforcing material. Nanomaterial may be a solitary or single phase one. The application in general will decide which material is to be used. Right material with right properties in tandem with the requirements of applications. Having said that composites may be better placed as it combines properties of both materials covering a range of properties.