Is it first date nerves or left over mental conditioning from being a JW ? As a JW we are taught going out with someone worldly was a huge NO ,NO that could only end in something bad .
Think through the situation and figure out WHAT you are really afraid of :
1) You know this man ,does he really seem like a serial killer ?? Probably not .
2)You already said "he is nice" so your gut feeling is he will be a good person to get to know further ......go with that
3) You are going to a public place with a friend and having dinner .....basic stuff people do everyday don't make more out of it than there is . Are you afraid someone from the JW world will see you on this date ?
4) A date is just a date it is NOT as we were taught in JWland were dating is not entertainment ,but the means of getting to know a prospective marriage mate. (News flash sometimes it is just entertainment nothing more .) Are you feeling pressure to make more out it than you should ?
Only you can figure out what makes you nervous . If it were me I would use common sense for precautions anyone takes with a first date , then I would go out and have an awesome time and enjoy my life .
Good luck to you have a great date !