You can see in the video that after she says "Lucha" I am about to repeat it and then I stop myself, because my first thought was, "there is no way she is saying Lucha, no way she remembers that!"
Probably one of the first times we looked at pictures I said everyone's name in my family photo, so how could she remember her specifically?
Well I have asked my Russian speaking friends, "Is there a word that sounds like "Lucha" in Russian?" The answer: Yes! It kind of sounds like "Lucha" quite a bit, and it means "better" like if you were comparing 2 things, and this one is better, then this one is lucha :)
So yes, Nina did say "Lucha" because it was the one Russian word that I had said that she understood while pointing at her auntie Luisa. She remembered! So Lucha, if you read this, you are the best!