How can we get nfet01v8 parameters value like vth, unCox, gm using simulation?

The question is a bit vague. If you want the device parameters you can find them by hunting in the spice include files. For example try skywater-pdk/libraries/sky130_fd_pr/latest/models/corners/tt.spice There are a lot of them so you’ll have to search for what you want. If you want to recreate the experiment they use to determine the parameters, but in simulation, that is a lot more nuanced and is more than can be typed in a slack post. A text I like on the subject is: Understanding Semiconductor Devices by Sima Dimitrijev It’s a good introduction and gives a lot of practical advice on various lab experiments and how the results can be used to find parameters for spice files.