If you are using your knowledge hub for the entire company, then it makes sense to organize content by department/role.

Create a manual for each department/role, and title the chapters within the role an area of responsibility related to the role.

If you are creating a knowledge hub for a department that services several different types of products or services, then a good option would be to create a manual for each product. The chapters within each manual would be different topics related to the product.

If your organization is more process-oriented and you have several large processes that span several departments, then you can create manuals that include process names. Within the manual, you can create chapters named after sections of the process or the various departments that perform the process.

If your organization uses several different applications, you can create manuals named after those applications. Each chapter would be a section of the application.