Scrollistic is a chapter based word processor for windows 10. It's free and available from the windows 10 store.
Scrollistic is geared towards novel writing but can be used for any writing format. It is especially helpful if you wish to e-publish your finished manuscript, supporting automatic generation of kindle and epub eBooks. Included are default styles for print and eBook or you can create your own if you know some simple CSS tags. Other features include automatic table of contents generation, ideas notepad, drag and drop chapter management and automatic backups.
Scrollistic is free but you can purchase an expansion which includes a dynamic character sheet and index creation. But the free version has everything needed to produce upload ready eBooks and certainly everything you need for NaNo.
Features useful for NaNoWriMo include a document word count, size of document over time and an alert when you reach your daily target word count. Being useful for NaNo was a prime consideration during the development of the software.
Scrollistic is a native windows 10 app, you can use it on any windows 10 device.