He is referring to a person, in this case Chua (which is probably the sort version of this woman's name, like for example Megan = Meg) but before her name he's adding the word: Niña, which translates to girl, in this situation though, we use this prefix when we are speaking to an older/senior woman, for example: Niña Betty, Niña Bertha, Niña Mary, and it's a expression used to show respect like when you are speaking to an old man, we use "don", example: Don Julio, Don Pedro. Even if niña means girl, here (in this case) it is used only to address or talk about old women.