Inhaling high temperature steam through the nose is NOT safe. It will likely result in scalding and damage.

At room temperature (20C), water vapor becomes saturated in air at around 2.3%. So in any sort of "normal" situation, even if the air contains a lot of water vapor, it is relatively low percentage and you can continue to breathe fairly normally with no issues as it will still be mostly normal air.

You cannot breathe liquid water because human lungs are not designed to extract dissolved oxygen from water. And of course, liquid water replaces the atmosphere which has the oxygen that the human body requires to survive. If you do end up breathing liquid water, this will eventually result in drowning.

Having said that, at elevated but still survivable temperatures (around 50C+), breathing air saturated with water is dangerous. Because the lungs operate at around 38C, water will condense out of the air and eventually fill the lungs. This will eventually result in drowning but slower (maybe a few hours). This situation can occur in certain caves (like the caves in Naica, Mexico also known as the Crystal Caves)