??? This sentence does not make any sense.
$$1\ watt = 1\ \frac{newton\ \cdot\ meter}{second}$$(
source)
You never specified what type of turbine you were referring to. Velocity triangles and the Euler turbomachinery equation still apply to gas turbines:
If you want to have the torque at stall then you will need to know the force acting on the blade, which is the pressure times the area.
The
maximum possible pressure will be half the density times the velocity squared. The area is the one from the outlet of the nozzle where that velocity is measured. That force times the radius of the blade it hits will give you the torque.
But the fluid never comes to a full stop when hitting the blade. The way the flow is deflected will affect the change in momentum and thus the actual force acting on the blade. So the geometry of the blade is still important. Even for a gas turbine. The Euler turbomachinery equation still applies; with the speed of the blade set to zero.