I can confirm the kobo Nia has an internal SD card : r/kobo

Kindle Basic vs Kobo Nia – Which one is better? - Good e-Reader

LIUDENWIN Universal Case for 6,6.8 Paperwhite E-Reader, Compatible with Kobo Clara HD/Kobo Clara 2E Leather Stand Cover for 6-6.8'' Pocketbook/Tolino E-Book Reader,Purple : Electronics

Kobo Clara 2e Review- Is it better than Kindle? BorednBookless

Kobo Nia e-reader Review - Good e-Reader

LIUDENWIN Universal Case for 6,6.8 Paperwhite E-Reader, Compatible with Kobo Clara HD/Kobo Clara 2E Leather Stand Cover for 6-6.8'' Pocketbook/Tolino E-Book Reader,Black : Electronics

Kobo 2E Internal Images - SD Card Confirmed : r/ereader

Kobo Clara HD - Coolblue - Before 23:59, delivered tomorrow

Escape into a story, learn something new, and remember why reading is fun. Kobo Nia’s a big deal in a small package: you can carry up to 6,000 eBooks

Kobo Nia 6 EPD w/ Carta display (1024x758) & ComfortLight (1024x758) & ComfortLight

Kobo Elipsa review: A versatile E-Ink ebook reader and notetaker

Kobo Clara HD - How I accessed & upgraded the internal microSD & bypass registration (Skip log-in)

Kobo 2E Internal Images - SD Card Confirmed : r/ereader

Kobo Touch 2GB, Wi-Fi, 6in - Black for sale online