I ask because I've never once heard about this again while trying to research it online so either he made it up or maybe it's just a Chilean local legend he got confused. Is there any evidence about Incans voyaging on the Pacific deep enough to have met any Polynesians /Pacific Islander?
It has not been proven, but it has been proven possible.
In 1947, a mad Norwegian by the name of Thor Heyerdahl decided to prove if the concept was feasible by flying to Peru, and building a raft out of balsa wood and other native materials in the manner that the Spanish conquistadores indicated was typical for the time, then pushing off with five other equally insane folks to sail Westwards. 101 days, and about 4,300 miles later, the raft, Kon-Tiki, made landfall in Raroia, proving that the incans, at least with 16h Century Incan construction knowledge, could have made the journey.
As an encore, the same nutter then decided to see if the Americas could have been colonized by Egyptians, and in 1970, he floated across the Atlantic on a reed raft named Ra II. (Ra I didn’t make it).
Of course, proving that they could, and that they did, were not the same. There certainly seemed to be indicators of ‘cross-pollination’ of cultures, with various artifacts looking very similar to those found in Latin America. In 2011, scientists using DNA analysis concluded that, indeed, there were American DNA found in Polynesian systems. So although the Polynesians almost certainly came from Asia, it would seem that either they sailed over to the Americas, ‘interacted’ with the locals, then returned to Polynesia with their families, or that the Americans indeed did travel across to visit, even if not settle with the Polynesians.
The third part is that if the Incans did make it over, were there any legends about it, as opposed to modern stories attributing to old legend. That, I do not know anything about Incan lore to verify.