Okoye -- who earned the nickname during his football days -- was Octagon-side Saturday to watch his countryman fight Tyron Woodley for the welterweight belt in Las Vegas.
Usman was the underdog going into the fight, but Okoye decided to attend to show his support for the UFC fighter ... who also calls himself the "Nigerian Nightmare."
Ya gotta watch the clip ... Okoye is beaming with pride and tells us how Kamaru will inspire a new generation of Nigerian athletes.
It's pretty cool stuff.
As for whether Christian is willing to pass the torch and hand over the nickname for good ... that ain't happening yet.
As for Kamaru, he's always had respect for Christian -- dating back to the first time we spoke with him back in February 2018.