head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is variance, and it is a single point.

Execution · Pure Mechanics
Punishing combat execution against fast scripted enemies with deep encounter solutions.

Execution · Practiced Mastery
A stance-action RPG carried by ki-pulse timing and loot build optimization.
Ninja Gaiden II Black leans Execution (Pure Mechanics); Nioh leans Execution (Practiced Mastery).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Ninja Gaiden II Black
Frame-tight blocking, dodging and combo routing define survival
Nioh
Stance and ki-pulse timing demand inputs
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Ninja Gaiden II Black
Aggressive enemies still run scripted, learnable behaviour
Nioh
Scripted enemies
Nioh leans a little harder on variance, though the gap is small.
Ninja Gaiden II Black
Encounters fixed; spawns known after one run
Nioh
Loot affix rolls
Nioh leans a little harder on optimization, though the gap is small.
Ninja Gaiden II Black
Weapon choice, essence economy and encounter solutions matter
Nioh
Build crafting and stance routing reward planning
A matching score does not mean a matching test. Two games can both sit at 10 on execution and demand completely different things of you - which is why the reasoning above matters more than the number beside it.