The nicotine is suspended in PG and/or VG with the nicotine level listed in mg per ml. The PG/VG is vaporized by the atomizer as it acts as a coolant to the heating element (why you should always keep your atty wet). So, without PG/VG you would be basically be burning concentrated nicotine with a car cigarette lighter. In my amateur opinion by burning pure nicotine and inhaling it - you would almost certainly die of Acute Nicotine Poisoning (assuming you're able to absorb it that fast through your lungs, I'm not a doctor or chemist my any means).
from wikipedia on Acute Nicotine Poisoning:
Sixty milligrams of nicotine, the amount in about five cigarettes or half a cigar, has the potential to kill an adult who is not a smoker if all of the nicotine were absorbed. 0.5-1.0 mg/kg can be a lethal dosage for adult humans, and 10 mg for children. It is impossible, however, to overdose on nicotine through smoking alone (though a person can overdose on nicotine through a combination of nicotine patches, nicotine gum, and/or tobacco smoking at the same time.)
If you didn't die immediately, you could look forward to some of these wonderful symptoms: Abdominal cramps; Agitation, restlessness, or excitement; Muscular twitching; Breathing - rapid; Breathing - stops; Burning sensation in mouth; Coma; Confusion; Convulsions; Depression; Difficulty breathing; Drooling; Fainting; Headache; Heartbeat - pounding and rapid, followed by slow heart rate; High blood pressure; Vomiting; Weakness.
I don't know anyone who has tried anything above 48mg. 42 mg's in my sweet spot, but that's really, really high for most people. 48 usually gives me a headache and almost instant hiccups (one of the first symptoms of mild nicotine poisoning), 42 is even a little too high for me if I'm chain vaping for hours, giving me an anxious, skin tingling feeling. But chain smoking 4-5 analogs, which was not uncommon for me on a lunch break or when under high stress, would also give me those symptoms.
Long story short: there are less painful ways to kill yourself.