The “Next Chapter” command sent to Apple TV from the remote should cause Infuse to start playing the next video file in the current folder if the current video file does not have any chapter markers in it, or no further chapter markers in it.
Currently, the “Next Chapter” command simply skips forward in time. There is no way I can see of immediately jumping to the next video, short of stopping the current one and then manually selecting the next one in the list. Which is somewhat annoying.