I think she is Brazilian. In the majority of her scenes, she claims to be Brazilian except for the one scene for 8th Street Latinas, but I think they made her lie in that scene. She looks Brazilian rather than Cuban anyway.
about nikki being or not Brazilian (don't know what is the point, but anyway...).
I am Brazilian and I can distinguish a Brazilian accent. She IS DEFINITELY NOT Brazilian by her accent. It sounds much more like a Spanish-speaker accent. Unless we are talking about a girl who was born in Brazil and very early went to the US and learned to speak English with Spanish speakers.