Panda Express labels their Orange Chicken as a "spicy" item but it's really not unless you are deathly sensitive to red chili peppers. It is probably the most popular dish at Panda Express, but probably also one of the least healthy entrees on the Panda Express menu. Still, it is awesome and an two-entrée platter is good for two meals with me.
As for taste, its starts sweet and finishes tart with just the barest hint of spicy. Honestly, many people won't even taste the spiciness, it's that weak. The red chili flakes are mostly for show, you could eat a whole batch of orange chicken and not feel the slightest heat on your tongue.
Some people might get sick of eating two-entrees worth of Orange Chicken but I never do.
If I were to compare them to another fast food item, I would say that they are like Chicken McNuggets sautéed in Sweet and Sour sauce more less lemony and more orange-y.
Nutritional Info - Panda Express Orange Chicken (5.7 ounce)
Calories - 420 (from Fat - 180)
Fat - 21g (Saturated Fat - 4g)
Sodium - 620mg
Carbs - 43g (Sugar - 18g)
Protein - 15g