Although chocolate chips can be used in place of dark chocolate chunks, I actually don't recommend it. Chocolate chips are designed to hold their shape so will resist melting as you want for this recipe. Only use if they are really all you have available.
Serving: 8g | Calories: 619kcal | Carbohydrates: 61g | Protein: 10g | Fat: 39g | Saturated Fat: 19g | Polyunsaturated Fat: 3g | Monounsaturated Fat: 13g | Trans Fat: 1g | Cholesterol: 131mg | Sodium: 331mg | Potassium: 582mg | Fiber: 6g | Sugar: 36g | Vitamin A: 746IU | Vitamin C: 4mg | Calcium: 156mg | Iron: 5mg