I think it would be hard to make it with a real japanese restaurant, with a measly hundred grand.
Now, more than ever before, there is a possibility it would work- there are more, edgier cuisine restaurants than ever before, many serving stuff that, only a few years ago, the "conventional wisdom" said argentines wouldnt eat.
But you would definitely need a knowledgable argentine partner, to navigate all the shoals- simply importing decent fish to serve would be a big hurdle.
Most world class japanese restaurants anywhere in the world- LA, London, Moscow, or Singapore- fly in fresh fish daily. Many have to fly in real wasabi, or nori, or even the right tasting burdock root.
Most of these authentic ingredients are just not available in BsAs, but, compounding the problem, importing stuff is harder, slower, and more expensive in Argentina than in probably 90% of the world.
Figuring out if its even possible to get daily air shipments of fish from Tsukji would take a while, and definitely require a connected Argentine partner.
Even in LA, really really good sushi can cost hundreds of dollars per person- and thats in a place with dozens of daily flights from Tokyo, and easy customs and import rules.
It is possible- restaurants like Olsen get stuff in, somehow, that you sure cant buy at Disco.
Argentine fish is not gonna cut it- the quality, and variety, is simply not there.
All the good stuff, worldwide, gets auctioned at Tsukji anyway, no matter if its from Chile or Alaska.
I dont think you would believe the stuff they call "sushi" here- canned tuna fish and cream cheese. Bastardized suburban california sushi, which there is made by mexican cooks in vietnamese restaurants, is better than most Buenos Aires sushi.
The worst part is- people here LIKE cream cheese on their sushi.
You absolutely have to come down for a month, and do your homework, before you even consider what kind of restaurant you could possibly open.
A ramen restaurant, something like Momofuko (except I am quite sure you aint no Chang) would probably be a better place to start.
Argentines already know they like noodles. And pork. And chicken. Miso, maybe a bit more of a stretch...