The number of calories in a chicken chow mein varies according to the manufacturer. It also depends on the serving size involved.
La Choy brand chicken chow mein comes in a can. It has a calorie count of 100 per 8.8 ounces, according to Calorie King. Contrast that to Trader Joe's frozen chicken chow mein, which weighs in at 240 calories per 6.7 ounces, which is about 1/3 of a package. Lean Cuisine also offers a frozen chicken chow mein dinner. It has 200 calories per package, which is 9 ounces as Calorie King shows. Other brands vary.