Why cannot I edit MOSFETs in LTspice by "nmos"
The problem is the vdmos model IRFZ44N already exists in the component databases.

  

Adding a .model IRFZ44N nmos(..) card will not change the type of the IRFZ44N to a monolithic mosfet.
You are therefore not able to manipulate the parameters of the IRFZ44N using .model nmos(..), but you can change them using .model vdmos(..)