An insurance is essentially a contract between two parties so you can find an insurer for almost anything...but it will cost you, dearly.
I would say you can get the insurance you want for roughly 30% of the value of the bike, per year.
Depending what model your bike is, not many people will have an interest in stealing your bike. The most plausible scenario would be someone using it in the country side, so actually some small towns are more dangerous than big cities in relation to bike theft.
I dragged a 5Kg chain from Texas to Buenos Aires, and I think I did used it once. Then on a subsequent trip from Mexico to Panama on a BMW, I learned the lesson and carried no chain at all.
Just do not leave your bike in the street overnight. Never. It does not matter if you have a chain or insurance, if someone steals say the carby, you are stuffed. So do not leave the bike outside.
And if you crash it badly as to be unrideable, just thank your lucky stars and go home, end of trip, done and did it.
There is ample information here and other places in regards to your question. Part of the kind of travel you are embarking on involves proper research. If you are going to go around asking every single question that pops in your mind, by the time you are ready to leave you will be 80 years old.
PS Transalps are quite common in South America henceforth the possibility of having it nicked totally or partially is higher than other bike models
- Amazing how many people who call themselves professionals are not professional at all