The First Amendment protects you from being jailed for using the word. So the police cannot arrest you for just saying the word. However, a decent person does not use the word. A private business can throw you out for using it. If you use it and a black guy punches you, that guy could use you saying it as defense his actions (whether or not it would work is debatable).
If you go on a rant screaming the N word on Tik Tok your employer can fire you and might be able to fire you even if it is a government agency.