Calories in alcohol-based sauce brought to boil (bourbon chicken)
Chronometer uses the best scientific-quality database, which is from the USDA's FoodData Central. You can find the same data at nutritiondata.self.com, which is easier to access from a desktop computer (in my opinion). 

The data set for 80 proof spirits is here. For all of them, bourbon included, the calories from not-alcohol is 0. All the calories in bourbon come from alcohol; there are no carbs, proteins or fats. 

The boiling point for alcohol in spirits is around 78 C (173 F). So if you get your food hot enough for long enough, you will eventually get rid of all the alcohol. Bourbon has highly concentrated alcohol, but since the recipe calls for a rolling boil and extended simmer, I would assume that you would remove all the alcohol through cooking, leaving zero calories behind in the sauce from the bourbon.