To standardize the look of the chapters across the entire book, import all of the formatting from one file to the others.
You can also just import the paragraph formatting (aka paragraph styles) from one file to the others.
Or, if you need to only change one style, i.e. ChapterTitle, you could edit the definition in one file. Save that file, then save it as a new file. Delete all of the other paragraph styles from paragraph catalog, save it again, and import the paragraph formatting (now reduced to the single style) to the other files in the book.