Bill check out the Members map in this Chapter. It will show you who is close to you.

Oh and Chips. I would go with either DP Tuner, Tony Wildman or Power Hungry Performance.
You will see alot of DP fans. He is the most popular especially with the SD's. TW is more popular with us OBS trucks. It is merely opinion.

One more option that may be best suited for you is Beans Diesel Performance. Actually now that I think of it Beans can do anything you want as far as codes, chips upgrades, turbos etc. And they are a great group of people to work with. Friendly, nice and helpful.
For even more mods Swamps Diesel performance is up the road from them too. And they are both in your backyard there in Nashville.