Going to be playing this game for the first time tomorrow.
Any tips for a newcomer? Besides the general stuff a person should already know playing by already playing Dark Souls
You're a ninja gaiden vet aren't you? You'll be more than fine once you master ki pulsing and flux, which is akin to a gears of war active reload system for your stamina. This allows you to play much more aggressively than you ever would in a souls game. Dodging has less iframes than in souls and certainly less than bloodborne so dodging through attacks is far less viable but certainly doable in low stance. Switching stances on the fly while fighting will bring that character action gameplay to the forefront as well.
Low stance = low but very quick damage, bloodborne/ninja gaiden style dodging
Mid stance = balanced damage, consecutive dodging will result in a roll
High stance = Big damage, very slow hits, dodging will always result in a roll
Feel free to play around with whatever weapons, skills and builds that interest you as it's very easy to respec. I recommend getting the kick skill for which ever weapon you are using, first and foremost, as this will teach you the importance of ki (stamina) damage. A big difference from souls is that you can see enemy ki(stamina) under their health. Once you've depleted it you can go in for a grapple move while they're vulnerable. There are different types of ki depending on if the enemy is human or yokai but you'll learn that and the differing ways to deal with them. I then recommend getting the ki pulse while dodging skill for each stance soon after that.
While it certainly wears its souls influences on its sleeve, I would also adjust your expectations depending on what souls means to you. If it means lore and level design, you will be disappointed by Nioh. What Nioh does have is a sublime combat system with diablo/destiny loot and mission structure. And you know team ninja, their stories are always batshit insane. Hope you have fun.