Thomas Nelson is now owned by HarperCollins, so they and Zondervan have started marketing together. A downside to this, though, is that Thomas Nelson books are no longer DRM-free at ChristianBook.
Anyway, they're having a year-end sale. I noticed some of these earlier and mentioned them (mostly Bibles, since that's what suits my fancy), but was just emailed a publisher page that links to lists of sale items at various ebook sellers. Kobo isn't one of them, but the books that I checked were the same prices at Kobo US and eligible for coupons.
Publisher link
According to the promo page, the sale ends January 3.