SouthernIM has it right above. Just talk to him like a normal human being; it's not rocket science. A good rule of thumb is that you should do more asking than telling. Ask about the department, who he would recommend as mentors, suggestions for research during the summer, etc. Every decent dept chair out there knows what's up and knows what students need to match in these smaller uber-competitive fields. You may even want to ask his thoughts on this very subject and what sort of things you can do now to make yourself a better applicant down the line. Ask which faculty he thinks would be great letter writers down the road with lots of national pull.
The publication/authorship conversation is something you should have with your mentors/PIs individually, not with the chair. And I ALWAYS clarify authorship plans/expectations before lifting a finger on a project. Again, this is expected and everyone knows that publications and authorship are basically academic currency so you can discuss it openly as professional adults.
In the end, I think the goals coming out of a meeting like this should be:
1) Make a good first impression as a polite, intelligent, interested, and ambitious young student
2) Make your face and story vaguely familiar to him for when you're back on service as an MS3/4
3) Learn about the department and what's available for students
4) Have a plan for next steps as far as who you will contact for mentors, projects, etc.
Bravo to you for taking the initiative and making these connections early. If you had the gumption to set up the meeting, you've probably got the chops to make a great impression.