spice netlist is required when using powermill(synopsys) to analyze power of the chip.
in Calibre, one command v2lvs is one way.
in panda, one command ver2cdl is another way to convert.
but, top module of the verilog netlist includes some IP which has no spice.
nettran in Hercules is another verilog to spice translator. You can merge the IP's CDL to the whole netlist. Or you can use nanosim to analyze the power.