Is NASA planning to synthesize ammonia using bacteria, or will it use the Nitrogen from Mars's atmosphere for the Haber process?
Ammonia is one of the top 20 key chemicals if you're starting up large scale industrial chemical synthesis, but does it have a specific early on use that would cause NASA to want to synthesize it early?
Wouldn't they need ammonia for plant growth on Mars, and also to use for nitrate synthesis?
And many other things. But I am not aware that it's an early focus of ISRU research by NASA.. That would be propellant.
You don't need a lot of NEW ammonia (or other nitrogen bearing chemicals) unless you're vastly increasing your biomass, I would think. Initial food production will use nitrogen from the waste stream.
It's a good question. ALL the key early feedstock chemicals have to be found, or synthesized, if you want a robust chemical infrastructure. Many important organics have some nitrogen in them ( for example, ABS, perhaps the most important plastic of all, since LEGO elements are made from it

).