I don't think the issue is as cut-and-dry as it is made out to be here. I think there are many things that come into play on whether a nano can be successful.
The main thing that concerns whether you can make a go of it is your states laws regarding it. For example if you can do it out of your home or garage, that reduces a lot of cost and could help make a go of it. The other thing that has a significant impact would be state taxes, permits, and licencing costs for the small brewery.
I would suggest researching your state laws for the state you live in or the state you are planning on the nano in (if different) to see how they they benefit and hinder the nano concept as a business option.