Couple things here:
1. She absolutely does say the N word. I couldn't tell what she was saying listening to the audio itself, but when you look up the lyrics for that section of Feeling Myself by Nick Minaj, they're "Then I curve that nigga, like a bad toss (Uh). Lemme get a number two, with some Mac sauce." You can absolutely tell that she's saying that once you can parse it out. So she is saying it, full stop.
2. She's allegedly been learning English for over 10 years at this point and is fluent, plus she's under YG, a company known for rapping, and has a passion for rapping herself; I don't really know how she WOULDN'T know about the N word in American rap music. Even if she didn't necessarily know it beforehand, it's just basic logic to look up words you don't know if you're going to perform a song.
3. YG, and really all entertainment companies, desperately needs to include basic training about this if they're gonna promote rappers; you can't interact with rap, an intrinsically black art form, and not educate your idols about basic history and black culture surrounding it.

She doesn't need to be removed from the group, she doesn't need to be 'cancelled,' but this shit is tiring and people need to stop acting like she did nothing wrong.