Sir, Is there a way to set a parameter of an instance (eg. nfet width), and create a second nfet instance that takes values (eg. nfet width) from the first instance.

In what tool? This is possible in ngspice; for tools like xschem it's a matter of getting to follow the ngspice syntax. Note that deep parameters are always a problem for layout (which does not have a way to represent passing of physical parameters through hierarchy) and should be avoided for that reason, generally, although there are times in which it is useful.

Sir using ngspice, just for simulation, matching 2 instance parameters, for sky 130 devices: cap and fets

@Saumeek Upadhyay: Should be something like this:

.subckt inverter in out vdd vss w=1 l=0.15
X1 out in vdd vdd sky130_fd_pr__pfet_01v8 w={2.5*w} l={l}
X2 out in vss vss sky130_fd_pr__nfet_01v8 w={w} l={l}
.ends

parameters can be declared on the

.subckt

line, and can be used by reference as shown.

Thank you very much sir. I apologize but is it possible to do this using ngspice in xschem

Xschem is all text-string based, so it is just a matter of, e.g., setting the value of W for a device to "{W}" and setting the subcircuit output line to include the text for the parameters.

Thank you sir