CONFIG_ARCH_BCM_NSP is not available for the default architecture x86.
Result is shown for architecture arm
default or selected kernelversion does not have config value CONFIG_ARCH_BCM_NSP.
Result is shown for kernelversion 6.0-rc7

Broadcom Northstar Plus SoC Support

modulename: bcm_nsp.ko

Linux Kernel Configuration
└─> Broadcom SoC Support
└─> Broadcom Northstar Plus SoC Support

Support for Broadcom Northstar Plus SoC.
Broadcom Northstar Plus family of SoCs are used for switching control
and management applications as well as residential router/gateway
applications. The SoC features dual core Cortex A9 ARM CPUs,
integrating several peripheral interfaces including multiple Gigabit
Ethernet PHYs, DDR3 memory, PCIE Gen-2, USB 2.0 and USB 3.0, serial and
NAND flash, SATA and several other IO controllers.

source code: