Yes, make a journal showing your workouts. Also what and when you eat in relation to your workouts and try to add anything else that could be helpfull like how you felt after a workout and what not.

Its hard to say what he/she will want or find usefull because every nutritionist is different.

Other than that just be sure to list your goals and any questions you have before going in so you dont neglect to mention them.

Good luck.