The whole point of farming nightmare dungeons in Diablo 4 is to get as much gold, gear, crafting materials, and XP as possible. The grind is also how you increase your chances of finding non-Codex legendary aspects that can only be obtained by extracting them from legendary items dropped by enemies and bosses.
That being said, you just do not enter a random dungeon to farm your endgame content. There are certain preparations to make beforehand, ways to choose the best nightmare sigil for the most rewards, and finally, a trick to reset the best nightmare dungeons in Diablo 4 so that you can farm them endlessly.
The following guide is going to show you how to farm nightmare dungeons in Diablo 4.
Make necessary preparations
Before you teleport to the nightmare dungeon entrance, make sure to empty your inventory so that you can bag as many items as possible.
Heal up and restore your health potions by speaking with a Healer in any town. Then drink any elixir for that all-important XP boost.
Only run nightmare dungeons +3 levels above you
To get the most out of farming nightmare dungeons, make sure that the nightmare sigil you are activating is at least three levels above you in Diablo 4.
Doing that grants you 25 percent more XP than normal, which stacks with your other XP boosts such as from drinking elixirs and playing in a party.
Confirm your dungeon affixes
For example, a nightmare dungeon with an affix that either doubles the amount of gold or magic items found makes it an excellent dungeon to farm in Diablo 4.
Reset nightmare dungeons for the most loot
If you have activated the perfect nightmare sigil, there is a way to keep running the same dungeon without the sigil expiring. What you need to do is know how to reset nightmare dungeons in Diablo 4.
Once you enter a nightmare dungeon, only complete its first area or level before leaving and entering another, normal dungeon and clearing its first area.
This will force the nightmare dungeon to reset and enemies to spawn back. Teleport back to the nightmare dungeon and repeat until you get bored. You do not have to enter another dungeon a second time. Just clear the first area, leave the dungeon through your emote/action wheel, and get back in.