If you set the difficutly on Nightmare and don't change anything it works as intended. But as soon as you change something like aim assist or parry timing, the difficulty changes to "Custom" and it overrides everything Nightmare is supposed to do (more dmg taken, less dmg dealt, less effective ration, etc...), making the game feel like it's on default mode or easy.
I hate controller aiming so I like putting the aim assist to "Full" but like I said, if I do that it feels like the game turns back to easy mode.
I appreciate the new settings but this completely defeats the purpose of being able to customize difficutly settings. I hope this is not intended. Easy way to fix that would be to separate the difficulty setting from all the other options. Like it used to be before today's update (TU 1.4.1).