Having played Nioh, so I can't really comment with that one in mind.
As for the rest, I'd say Dark Souls. It has some brilliant dungeon designs (with the only downside that, unfortunately, Anor Londo exists in a separate hub/screen, so to speak, so it's not entirely entirely connected), truly memorable bosses and leaves you with a sense of achievement that's just pure enjoyement. Also the game is rich in several departments, such as lore, customization and the likes. It has its flaws, but for me it's just the one that strikes the best balance on everything while actively being fun.
Second one would be Bloodborne. The only reason Dark Souls is first for me goes with the fact that I played it first, as I think Bloodborne's strengths are equal to those of Dark Souls (and coincidentally, they share very similar flaws).
