default or selected kernelversion does not have config value CONFIG_DRM_NOUVEAU_DEBUG.
Result is shown for kernelversion 6.2.5

Build in Nouveau's debugfs support


Linux Kernel Configuration
└─>Device Drivers
└─>Staging drivers
└─>Build in Nouveau's debugfs support
In linux kernel since version 2.6.33 (release Date: 2010-02-24)  
Say Y here if you want Nouveau to output debugging information
via debugfs.