Chin-Na is a component of many Chinese systems. Some having more, some having less. Systems like Northern Eagle Claw, Northern Mantis, White Crane, BaGua, to name a few all have Chin-Na components.
A major influence as spreading information on Chim-Na is Dr, Yang Jwing Ming. With a background in several Chinese systems, and also with the logical mind that goes with a PhD in Engineering, by the 1980s he saw the relevance on sharing that for other martial artists through clinics, programs, books and video tapes.
Being most logical his books detailed many of the components of Chin-Na training. They accompany the many fine video’s he created.
I had attended a clinic and workshop he gave on various arts. But Maureen Smith, my wife, took a 9 month course he offered on Chin-Na back in 1989. I was her practice partner, It was a painful time.
A great many of his videos may be found on YouTube, This is an example:
The following are among his many books, these are on the variety of Chin- Na training.
There are other publicans and videos on Chin-na, many of them are also worthy.
While not exactly a practice of original karate, it does offer logical movements that can combine with karate.