Here is an online source for the one SCOTI showed above, $15 each:
https://www.rivetsonline.com/rivet-n...et-nut-tools#1
These are a bit higher priced, but look to be built to last longer..
https://www.rivetsonline.com/rivet-n...ss-nut-tools#1
Here are a couple of other simple rivet nut installation tools:
https://www.aircraftspruce.com/catal...vetnuttool.php
6-32, 8-32, 10-321 thread sizes only
https://www.aircraftspruce.com/catal...onrivtool1.php
This one is limited on the thread sizes available, 1/4"-20 or -28 is the largest