Hi,
I don't know it there is a mistake on your message, but you inserted the lines on:

recipes-packages/images/sample-image-cp-lwb5plus.bb

but then you are searching the tar on image name "

tmp/deploy/images/machine-name/my-image-smarc-rzv2l-<date>.rootfs.tar.bz2

Unless you include/inherit the file sample-image-cp-lwb5plus.bb on my-image-smarc-rzv2l.bb file, this wouldn't work.
You should make sure the IMAGE_INSTALL is correctly appended on the image file you are compiling. To debug this, you could print the IMAGE_INSTALL variable for the image, and see if the nmcli package is there:

bitbake -e sample-image-cp-lwb5plus | grep "IMAGE_INSTALL="

Another way to check what is installed on the image is to open the manifest file on the deploy directory (*.manifest)