Caribbean Latinos in NYC and FL been saying nikka since the 80s. In person and on rap records. It's crazy cause I never heard anyone having an issue with it until I came across internet forums in the 2000's. And I think that is because you could hear perspectives from other regions, like the south (excluding FL of course) where they grew up just black and white, and not many Latinos... and that shyt is unheard of to country black folks. It's a weird thing. Not saying Caribbean Latinos should be the only ones "allowed" to say it, but I do feel funny about other Hispanics like Mexicans or Guatemalans using it. I feel like they only started saying it in the last 15-20 years due to rap music culture.. before that they were pretty strict about not using black culture slang, and stuck heavy to "ese", "wey", "foo", etc. The Caribbean Latinos in NY and FL were just ingrained with it from the jump, based on cultural surroundings and intermingling living situations. A Southern Cali Mexican would not have intermingled with blacks like that back in the day, very segregated. They saying that shyt now just cause of rap music, not cause of their local culture. Bay Area is different (a whole nother world), they got they own politics and seem to accept Nortenos saying it. I don't know much about Houston, but I still feel like H-Town Mexicans weren't saying the word all that much until these younger generations came about.
At the end of the day, there is nothing that can be done about this. It will only continue. You beat down one person for using the word.. and there's millions more out there saying it. It's a battle that can't be won, can't be policed, can't be stopped. Maybe if the day ever comes that black folks universally declare to stop saying the word and make it not cool anymore, then others would follow. Just like its not cool anymore to say "funky fresh" or put an "MC" before your rap name. That is the only way it would cease.