Part of the Black Panther's job is being the first warrior of Wakanda, and in that role, Okoye would excel. The leader of the Dora Milaje has proven herself time and time again in battle, and that leadership role could certainly translate to a more public leadership position if she is called upon.
With that being said, Okoye is probably a less likely candidate to take up the Black Panther legacy. The trailer consistently shows her with the Dora Milaje, cementing her status as their leader first and foremost. As something of a stickler for tradition, Okoye doesn't seem like the kind of character who would make a claim on the throne or even accept it if offered; she's more likely to be a key advisor and guard for whoever does become the new Black Panther.