Nesting Grounds is an Azurite Mine node. It can only be found in Petrified Forest biome. It usually contains generic loot as stated in the node description, or more rarely, Contains Physical Items, which contains physical-related unique, fossil and Delve drop-only modifiers.
There is 4 nests that the players need to ignite by clicking them. Player can clicking them one by one as the nest will spawns adds. Otherwise player can challenged themselves by click them all in a short succession.
After all 4 nests are ignited and reaching certain amount of Bone Rhoas killed, rare Rhoa(s) will spawn as the bosses of this node. Killing the rare Rhoa will complete this node. However, sometimes there may be some adds left, so that player must kill all the adds or otherwise risk losing the loot by dying to the adds, after the node is completed.
These modifiers can only drop from Contains Physical Items version of this node: