Very hot water and you'll be OK, but still wear protective clothing and eye protection.
The Nitre still clinging to the parts will spatter when hit even by the extreme hot water.
The water can only be as hot as 200F+. The part with the Nitre still on it will likely be around 550F yet right out of the Nitre Bath.
Let the part cool down some with the Nitre still on it. You will see the Nitre crust over to a white coating.
The hot water rinse will disolve it even then with no problem to remove it.
I usually just hold the crusted over part under the hot water tap in the sink.
Don't ever get even a single drop of water into the Nitre bath itself or you will be blanketed with molten Nitre. It burns through about everything.
No water or water source should be anywhere near the Nitre Bath.
Once the Nitre is removed with the hot water, you can then use cool water to further cool down the part(s).
Or better yet... just let the heat remaining in the steel dry the part on it's own (takes just a few seconds usually)
and then dip them right into some oil.
The oil dip while still hot/warm usually darkens the color,,but not always. Depends on the alloy of the steel.
