Does nitrogen deaeration need to be performed in a fume hood?
As implied in the comments, you have nothing to fear by sparging your solution with nitrogen in the classroom. Even a good size tank only contains a few cubic meters of compressed gas, while your classroom likely contains a few hundred cubic meters of air. Thus, even if you could instantly empty the tank the effect would be negligible. And you will be using low enough flow rates that there will be no fear of a "localized" depletion of oxygen.  

The safety issue that I need to mention, though you are almost certainly already aware, is regarding the sodium hydroxide solution. Even at $\pu{0.1 M}$ it's not something that you want in anyone's eyes, so protection against splatter from the sparging solution would be prudent.