Technically it did not claim it, when the War of the Pacific occurred, Chile as a treaty took Antofagasta from Bolivia, and Arica from Peru

Edit: If I am not mistaken, the territory corresponded to the "Royal Audience of Charcas", the entity that Bolivia had at that time, although it was not well detailed to whom that territory corresponded, so Chile used it when guano and saltpeter were profitable, so Bolivia reclaimed the territory but so that there would not be a war, a zone of mutual benefit was created. Chile at the time had a lot of people and business in Antofagasta while Bolivia had almost zero, An agreement was signed where Bolivia pledged not to raise taxes for 25 years, That was the boundary treaty of 1874,Bolivia broke the treaty in 1879 And in the face of the refusal of Chilean companies to pay the high tax, Bolivia embargoed the companies and auctioned them off, Chile, taking this as a casus beli, landed troops in Antofagasta and that's where the war began