Why does Argentina think Nepalese are their enemies?

Argentinians rarely have Nepal in their minds, by any means.

Most of the population probably ignores the straightforward existence of Nepal.

Argentina, because the government structure, and as its population, has no considered Nepal (or its population) being their enemy.

Oh! does one mean Gurkhas?

The British government made them famous before the primary clashes during Malvinas / Falkland Islands war happened. They were presented as courageous and really wild soldiers. That wont to cut the ears of dead opponents.

That was the parable . Reality was different. No wild behavior. Just brave soldiers. only a few people remember them in Argentina. and no-one relates them with Nepal, neither hates Nepal due to them.