The bread (it varies based on type, size, brand, ect.) is probably, assuming you have 2 slices, between 150 and 200 calories, and the lettuce is 30 calories. So the sandwich in general is probably about 180 to 230 calories or so.
The calorie content of a chicken sandwich, or a chicken salad sandwich, depends on what ingredients (in total) are used to make the sandwich (including any dressing) and the quantities of those...
You would need to check the packaging of every item in the sandwich, figure out how much of each item you're using, and then add it all up. There is absolutely no one calorie total for all...