Patch 1.1.1, which releases on August 8, will increase the monster density for Nightmare Dungeons and Helltide!
Diablo 4 Patch 1.1.1 Campfire Chat Summary Nightmare Dungeon Guide Helltide Guide
During the Campfire Chat Livestream, Blizzard has shown an example of the new monster density for the Nostrava Deepwood Nightmare Dungeon. The example shows a significant monster density increase of 58%!
Monster density in Nostrava Deepwood before (left) and after (right) the release of Patch 1.1.1.