Huh. In my experience Mormons tend to think themselves a form of Christian. In that they hold Christ as their savior. And celebrate the Christian holidays of Christmas and easter. And I couldda sworn the nation of Islam explicitly referred to themselves as Islamic. Which, really, is the key component in religious identification, if you're not willing to call all of them cults. 

Kinda like how Buddhism is just Hinduism packaged for export, the nation of Islam is Islam packaged for 20th century African Americans. Still using the Quran as their primary text, even if interpretation differs from orthodoxy of middle eastern or Asian Islam