During Red Dead Redemption 2's story mode you have the chance to hunt for treasure thanks to treasure maps. These hunts can be quite complicated, as you have to head from one point of the map to another in search of more clues that will set you on the right path.
Like for all of the game's mechanics, Red Dead Redemption 2 does its best in terms of easing players into them, and the same goes for treasure hunting, as one of the first treasure maps you will acquire will likely be Chick's treasure map.
Chick Matthews appears in the eighth Chapter 2 story mission, Money Lending and Other Sins. In this mission, the Van der Linde gang's bookkeeper Leopold Strauss asks Arthur to recover money that has been lent to people who have failed to pay it back.
Chick Matthews is located in the New Hanover region, in a farm found right to the south of the "S" in New Hanover. As soon as he spots Arthur approaching his farm, he will try to make his escape. Follow him on horseback and get your lasso out to hogtie Chick as soon as he is in range.
Once he has been hogtied, you must loot him. Matthews has no money or gold bars on him, sadly, but Arthur will recover a sketch (Chick's map) which reveals the location of Chick's treasure, which will cover the debt he owed to the Van der Linde gang.
The location depicted on the map is not too far from your current location: it's by the train track to the north of the "N" in Hanover on the map. After reaching this forested area, you must check the largest tree in the area: there should be a hole in the northern side of its tree trunk containing the treasure.
This is only a small warm-up for the real treasure hunting that can be done during RDR2's story mode. If you haven't had enough of it, you can start looking for the High-Stakes, Poisonous Trail, and Jack Hall Gang treasures.