it's just a gag
So was "Zoros coc moment".
Odas not just gonna joke about a character having CoC and then drop/ignore it. Its not impossible for him to but it would be completely stupid of him to.
Nami has been hinted at having it for decades now maybe, at least since Water 7 at earliest minimum. Maybe longer.
She's like a hononary vice captain or even captain at times, has shown extreme willpower especially in resisting Arlong for over a decade and keeping strong despite the trauma of seeing Bellemere coldly murdered in front of her as a child too.
Nami is extremely underrated.
Oda LOVES Nami, he even married a Nami cosplayer ffs so you really think he won't hype her up and give her CoC too? We know its not exclusive to captains, that any crew member can have it potentially and even Marines like Sengoku.