There is an issue with uname -m on the Raspberry Pi 4 in which the wrong system architecture is reported when a 32-bit OS is used. The result is this error when attempting to run the nvs installer:

pi@raspberrypi:~ $ . "$NVS_HOME/nvs.sh" install
Downloading bootstrap node from https://nodejs.org/dist/v16.20.2/node-v16.20.2-linux-arm64.tar.xz
######################################################################################## 100.0%

-bash: /home/pi/.nvs/cache/node: cannot execute: required file not found

To workaround this, I hard-coded the architecture in net.sh.

More specifically, I changed this line:
local NODE_ARCH="$(uname -m | sed -e 's/x86_64/x64/;s/i86pc/x64/;s/i686/x86/;s/aarch64/arm64/')"
to:
local NODE_ARCH="armv7l"

This forces the installer to use a 32bit version of node and the installer succeeds.