If I was found admissible to enter the US through a B1/B2 visa about year ago, but never went to the US, and recently was returned to my country while trying to visit Chile for tourism by the migration officer, may the antecedent be a conflict at the time to arrive the US as a tourist?
US border officers can refuse entry to travelers for almost any reason (except a short list of legally protected characteristics such as the traveler's race, religion, gender), even when the traveler has a valid visa.
The can reject you because they don't like the color of your shoes, or because you were refused entry in a different country.
Will they refuse on that basis? Probably not, and definitely not automatically. If there's a notice of the removal in your passport, this may occasion some questioning about what's up with that.
(Psychologically, US government agents pride themselves of maintaining higher standards of liberty and justice than damn well the entire rest of the globe. Whether this self-image has a basis in fact is, to put it mildly, hotly debated -- but they sure as heck are not going to lean back and give some random Chilean border worker an automatic veto on who they're letting into their country, without making an attempt to figure out the matter for themselves).