There WERE talks of it, but I am not too sure how'd that work out.
Besides, last time we tried, we kinda got our asses handed to us by Argentina and Chile.
I suppose it could be done, but it would lead to a massive Civil War that WILL result in Chilean intervention.
However, if this also leads to a Guerrilla war, a chance could happen of Chile being bled dry to exhaustion while warring in the Andes...