Before you click on click on covert Kicad to NGspice, you should have created the .cir netlist for it. The procedure for that is : 1. Click on Generate Netlist button. 2. Click on the SPICE tab [ THIS IS VERY IMPORTANT], select the default format window, and click on Generate.
Is it possible you created some other netlist other than .cir?
Please make sure that you also the components from esim libraries only.