It is a phrase that suggests that Nina is engaging in a conversation or discussion about love. It doesn't provide any details about what she is saying or the context of the conversation.
To get a clearer understanding of the meaning, you would need more context, such as:
* Who is Nina talking to?
* What is the situation?
* What is the tone of the conversation?
Without this context, the phrase "Nina hablando de amor" is simply a statement that Nina is talking about love.