A lot of Spanish speaking memes and videos I see have this running joke that Chileans are hard to understand. I don't think it's a literal truth or meant to be taken seriously. They just hand pick a few examples of people who talk very fast, which exist in most Spanish speaking countries (in Spain, Andalusia would be it). There are similar videos in the same circles talking about how hard English is based on a drunk American redneck fisherman or Adele's working class London speech. It's just a meme.

These memes are popular in Latin America, it's definitely not just a Spain thing.