default or selected kernelversion does not have config value CONFIG_NET_VENDOR_NUVOTON.
Result is shown for kernelversion 6.9.9

Nuvoton devices

configname: CONFIG_NET_VENDOR_NUVOTON

Linux Kernel Configuration
└─>Device Drivers
└─>Network device support
└─>Ethernet driver support
└─>Nuvoton devices
In linux kernel since version 3.1 (release Date: 2011-10-24)  
If you have a network (Ethernet) card belonging to this class, say Y.

Note that the answer to this question doesn't directly affect the
kernel: saying N will just cause the configurator to skip all
the questions about Nuvoton cards. If you say Y, you will be asked
for your specific card in the following questions.