Gold Nuggets can be found by mining Boulders (with gold veins on their side) or Stalagmites (found only in Caves). They can be found lying on the ground in Graveyards or Rockybiomes, and fall from the ceiling in Caves during Earthquakes. The Pig King will also exchange Gold Nuggets for certain items.
Like most other minerals, Gold Nuggets can be eaten by Slurtles and Snurtles, and Slurtles will attack a player carrying it if there aren't any other minerals in the immediate area.
In the Shipwrecked DLC, Gold Nuggets can be Refined from Dubloons. Digging gold flecked Magma Piles can yield Gold Nuggets. Unlike gold veined Boulders, gold flecked Magma Piles do not have a preset amount of Gold Nuggets to drop. Instead, there is an independent 25% chance for each dug up item to be a Gold Nugget. Therefore, there is a small (~7.5%) chance to get no Gold Nuggets, and a very small (~0.00038%) chance to get a total 9 of them from each Magma Pile. Very rarely, Gold Nuggets can be found laying around in Jungle and Magma Field biomes.
This DLC also introduces many new methods to obtain items, most of them include Gold Nuggets as a possible reward, however, typically chance of getting a Gold Nugget among all possible rewards is small and some of these are chance encounters, therefore these cannot be used as a reliable method to obtain Gold Nuggets. These methods include:
In the Hamlet DLC, Gold Veins are not present, so the task to obtain Gold has become more difficult. It is still possible to mine Gold from Stalagmites, but Stalagmites themselves are rarer, and can only be found in Cave Clefts. However, new methods has been introduced to obtain gold:
Pig Statues can be chiseled with a Ball Pein Hammer to obtain 2 Gold Nuggets.
6 Gold Dust can be refined to obtain one Gold Nugget (however, 3 can be dropped near a Pangolden for it to convert into 1 Gold Nugget).
If a Secret Bandit Camp treasure chest is open, there is a 1/6 chance to obtain 4 Gold Nuggets.