Common source amplifier using mosfet: Why is my Id dependent on my Rd?
Your Rd is 150 k ohm, that means that Id can never be more than 10 V / 150 kohm = 67 uA.

Now suppose the NMOS wants (according to the formula for Id) 100 uA to flow.

Who would "win"? The Resistor Rd or the NMOS?

I suggest that you do a DC simulation where you vary the value if Rd from 0 (zero) to 150 kohm and observe what happens to Id.

Only in the flat (horizontal) part of Id vs Rd will the NMOS be in saturation mode and will that formula for Id be valid.