From my understanding, N has become essentially obsolete for its former "legitimate" purposes. As much as a vet or pharmacist from the developing world might want to sell it to us at an insane profit margin, when they lose access to it so do we. The companies that historically manufactured it have cut production to essentially 0, and unlike other illicit trades where criminal enterprises have stepped in to meet demand, we don't represent a large and sustainable enough market for a black market manufacturer to bother with making N.