Think hard.
They elected him, it was their problem. If Nixon had been wise, he would have let the Chileans crush Allende at the ballot box.
Allende was freely elected. However, within a few months he was a dictator who did not follow the law. I'm pretty sure he had suspended all elections so that he couldn't be voted out if we merely did nothing. He was having orgies at his presidential palace, inviting lawmakers to the orgies and getting them on film in compromising situations, then using it to blackmail them. He was considered a truly bad character for what he did after he came to power, the democracy was dysfunctional at that point. He imposed some communist rules on the economy so that things were coming to a standstill. Food was not coming into santiago, the population was getting hungry. You couldn't buy bread and other staples in the markets in the days leading to the coup. People were rioting in the streets. All we did was work with the Chilean military to get allende out. It was in fact necessary at the time. The people stopped rioting in fact after allende was killed. But allende was a communist who was elected, the US helped get rid of him, so we are the bad guys and allende is the good guy according to the liberals. But since we helped get rid of him, chile has become the most prosperous nation in latin america. Their economy is kick-ass. They have a stable democracy today. Chile benefited enormously from getting allende out and pinochet in. Argentina, Brazil and Venezuela all envy chile over what has happened since the early 1970's.