Nanichi is the Arawak (Taino
)term for "my dear/my love/my beloved" etc. It is used by many Puerto Ricans on the island of Puerto Rico and a few in largely populated Puerto Rican areas (New York City, Boston, Chicago, etc).
Some Dominicans and even some Cubans also use the word due to the fact that the Arawak language was widely used throughout the Caribbean islands.
"Hey, nanichi... what's up?"
"I'm sorry, nanichi. I didn't mean to."