Can an INFP be outgoing and social and so very chatty when the occasion is right?
Yes. I am chatty with the right people / situation. It's just that I don't have the skill to sustain conversation with people who are not interested or a conversation I am not interested in.
I think I am an extrovert because I am genuinely concerned with, and affected by people, and the human condition. I think people can be fascinating, and I love trying to figure people out, and learning other people's perceptions of this thing called life.
I could say the same. But I am very sure I am an introvert.