Let me start by saying that if it was just food that I was evaluating it would have been a 4 star rating...however, I have to rate the entire experience. My partner and I visited last evening and had a nice dinner - food was excellent, the popcorn that they serve when you first arrive is very flavorful and the wait staff was efficient.
After dinner however, we decided to stay to have a drink or two at the bar - this is where things went south. They had one bartender serving the entire restaurant and she was simply overwhelmed. It took more than 10 minutes to get a beer and once finished took at least 15 min for her to even notice that our beer and wine glasses were empty. We wanted to order an appetizer to snack on, but simply couldn't get her attention. For our check, we had to stop the manager and ask for our check, which he brought to us after another wait period. Bottom line, they really need help at the bar during the peak hours - they honestly lost money we were ready to spend on more food and drinks....
If you are going to Nan and Byron's, expect good, unique food choices - but expect a long wait for drinks, unless we came on a fluke day where they were simply understaffed.