Unlike other ores in the game nether gold ore doesn't reward the player with any experience when mined with a pickaxe, this could be intentional considering the ore can be collected using silk touch in order to receive experience by smelting it as a trade off.
MC-175224
Nether gold ore does not yield any experience when mined
Resolved
Fixed
11
Yes, since nethergold can be harvested using several methods (pick for 2-5 nuggets, fortune3 pick 8-12 nuggets, silktouch +smelted for 1 ingot), seems you should be able to get exp if using pick or fortune3 pick, since you won't be smelting it.