I live here and never heard of that...
But well, looking around for a bit, is not really an established amount. You just need to proof you could survive here on your monthly income (or savings).
This site (go down to "Retirement Visa") tells is about $1000 per person. But really, it depends. If you try to live in Santiago, life expenses are higher. Even, if you live in Las Condes, is more expensive than Maipu (two different zones of Santiago).
Now, if you don't go to the capital, things are probably cheaper, but getting stuff done is also difficult. For example, catching a good cultural show is probably easier in Santiago because of the amount of offer there is, while in Puerto Varas there are few and far between.
Also, you have to keep in mind the value of dollar changes every few years, so calculate the exchange rate of your dollar income on the lowest and biggest rate (normally between $500 CLP per dollar and $750 CLP is the highest I've seen so far) so you don't go through major rough times.
My advise is: decide where you want to live, check the cost of living there, do maths, and just apply. Because there's no amount set on stone.
I'll leave you with a quote from this site
Chilean immigration for the most part will not tell us or anyone else
exactly what the magic number is in terms of monthly income or other
assets that is required to qualify. All they will say is that it must
be sufficient to live on in the area you are intending to reside. So,
for example it is much more expensive to live in Las Condes in
Santiago than a small town in Southern Chile. A good rule of thumb
across Chile is that you should be able to show $1,000 US per person
including yourself and any people you claim as dependents on your
application. This is sufficient to live a middle class life style in
almost every part of Chile.