Nick represents a familiar aspect of your own actions or behavior. When you think of his personality, those traits you see in him are the ones within you that the dream is addressing. Lazy/hard working? Honest/dishonest? Focused/scattered? You are beginning to act in a way that is similar to his personality.
As he flirts with you, this shows that you are gradually acting in a way that is starting to, or trying to become more visible in your life. In other words, you are finding yourself on the edge of doing something that you normally wouldn't do. Your mom represents your higher, loving self. It is this part of your thinking that snaps you out of it.
Look over your life and see where you are on the edge of acting or behaving differently but can fight it off with your higher self. How you see Nick is key in understanding what you are 'almost' doing.
This may not be what you were expecting but I hope it helps. God bless.