How ‘lively’ would this ‘health’ potion be?
Explosives: It is true that sulfuric acid and sodium/potassium nitrate are used to make various explosives (by creating nitric acid), but the key is something to nitrate. The worst this mixture could generate is nitrated ethanol, and I was unable to find any source suggesting that could be done with nitric and sulfuric acid alone. Nitrating a molecule that small with that simple of a structure seems unlikely without extreme conditions or reagents. If it were possible, the most likely product does seem to be something unpleasant.

Poisons: What definitely would be produced is nitric acid, and the production of nitric acid via sulfuric acid and a nitrate salt produces nitrogen dioxide, a poisonous and caustic gas. This is some seriously bad stuff you do not want to come in contact with.

Based on that, I'm going to conclude this mixture is probably not explosive, but definitely could become so if an easily-nitrated compound was a contaminant. Those are more common than you might imagine. It definitely would create a nasty gas.