The phrase "a substantial chapter" is correct and usable in written English.
It can be used to describe a chapter in a book or document that is significant in length or importance.
Example: "The author dedicated a substantial chapter to discussing the implications of climate change on global economies."
Alternatives: "an important chapter" or "a significant chapter".
I recall how, at a Muslim conference in Chicago, a Turkish man approached a stand where an Armenian was selling books on Middle East history, one of them a book of mine, which includes a substantial chapter on the Armenian genocide.
For a broad overview of scholarly work on genocide in world history, see The Historiography of Genocide, which includes a substantial chapter entitled "Genocide in the Americas" and another entitled "Genocides of Indigenous Peoples".
Still, within a global history of abstraction, the Western variety has its own substantial chapter, one that is still being written.
Pinker assumes that many of his readers will be skeptical of this claim, so he spends six substantial chapters documenting it.
Inefficient companies could gain a substantial advantage in Chapter 11, because they could continue in business without having to service their debts.
Twice as hefty as its predecessors, "Harry Potter and the Goblet of Fire" is an uncommonly good-looking book, with a substantial feel and artful chapter illustrations that anticipate the narrative.
Likewise, a substantial portion of the chapter on B. burgdorferi in the vertebrate host is devoted to the role of complement in host specificity.
The new edition includes a substantial new introduction, additional chapters and an afterword to reflect recent political changes.
There is a substantial and structured overview of references in the chapter of related work, focused on the problem.
After deciding to sell his shares in the company at a substantial profit, Mr. Leiweke said, he faced the next chapter of his life.
The lingering mortgage crisis has finally reached the bankruptcy courts in a substantial way with the filing of Residential Capital's Chapter 11 case on Monday.
