What possibilities do I have to get some kind of work?

Hi Agunob!
At the risk of being blunt, let me answer you in one word: unlikely!
First major consideration is for you to decide as to whether you just want to "visit" Nepal, in which case you are necessarily limited to a 5 months/Tourist Visa in any 12 months period (with no right to work for that duration of time) OR
whether you think you'd like to live and/or work in Nepal, in which case you'll have to - or your employer has to - apply for a work permit and if you are fortunate with your application, you get a one year business visa (renewable at expiration)
Personally, my strong advice to you is to make every effort to secure a job opportunity in Nepal before you leave Argentina. Take your time! If I can give you any advice, try your best to come to Nepal with a one or two year work contract in lieu of a job application!  To do that, you may want to talk to people in Argentina who know the country and have ties, business and otherwise, to Nepal? Consult the web to see what international companies or organizations are operating there, and contact them directly? Make a list of all the ones you think you'd like to work for - depending on your qualifications - and, submit your Bio-data or Curriculum Vitae - to as many as possible....twenty to thirty...why not?
I'll give one big hint. The foreigners in Nepal who enjoy a good standard of living are in so many cases associated with an international NGO. So the NGO could be from Argentina, or some other latin american country? The point is that if you can land a job before you depart for Nepal, it is the NGO or the company as the case may be, which will be the one who will automatically assume the responsibility of applying for and obtaining for you, the required work/residency permit for the full duration of your stay in Nepal. 
And if you can manage to get that medium to long term contract, you can then live in Nepal under quite favorable conditions, have a nice apartment, etc.
If, on the other hand, you arrive in Nepal "empty handed" ....with no more than just  a job application,  no guarantee at all of your being able to get a decent job, and at a salary which in any case will be at the much lower level of a "nepalese salary" - So which might you prefer: being paid a considerably lower nepali salary or on the basis of a substantially higher western/international salary? The first one will be payable to you in Nepal in non-convertible Nrs. The second one is likely to be paid to you in dollars to your account in Argentina, or other but abroad, and with the added advantage of being in a convertible currency.
This having been said, I would advise you to read up on Nepal and learn as much as possible about the country, its people and the culture prior to leaving Argentina. Consult UN sources, UNICEF, World Bank sources etc, As you will learn, Nepal is one of the world's poorest countries; south Asia's third poorest according to the World Bank, with 33,9% of its population of 31 million living on less than $1.25 a day. So there is a huge amount to do to try and assist the country and its people.  I don't know what field you are in, but education in Nepal needs teachers, just to cite one field/example. According to the Nepal Living Standards Survey 2010/2011, 56% of females and 28% of males aged 6 or above could not read or write a simple sentence (UNESCO 2015)
Nepal's big neighbor - India - is a developing country. Nepal is still an underdeveloped nation.
Now, it is your decision as to which way you want to proceed  but, personally, I would not count on getting a good job here. I don't even know if you would find a single employment agency to turn to, for help in your case. All the employment agencies I know of in Nepal are too busy sending nepali workers to Quatar and other Gulf countries. As for the level of unemployment here in the country, it stands at almost 50% of working age population, with 1/4 below the poverty line.
Hope this helps. Let us know what you decide to do!