If "hasbuna Allah wa ni'm al-wakil" could protect from fire (Prophet Ibrahim), it can protect from anything else.
"Allah is enough for me and what a blessed source of reliance."
Notice that the dhikr actually does not ask for a stoppage of the perceived harm. Rather, it simply states that I'm relying on Allah, because He knows our situation better than we ourselves know it. The thing I fear may actually be good for me. But the dhikr will make it painless, just as the fire did not go away for Ibrahim, but it became painless. In fact, Prophet Ibrahim later said the greatest time in his life were those days in the fire. Jibreel would come down twice a day and eat with him. Likewise Prophet Yusuf in the well.