Quick service burger chain Whataburger Restaurants has announced it is adding a chicken fajita dish to its menu. The chain’s menu already included a chicken sandwich and chicken tenders.  The Chicken Fajita Taco will be rolled out in the chain’s 700-plus restaurants in 10 states as part of a lower-calorie offering.  The taco has 420 calories and joins other lower-calorie options like apple slices, instead of French Fries, and new salad choices.