I am not sure a link to the tool is necessary, If you have used the tool in the past you would understand the tool. The name of the tool, as you have stated is arduino-fwuploader and I also mentioned in my post. I appreciate, for I did not know, you can pas multiple files to the --file flag. That helps.
But this really doesn't answer the question in the post. "Has anyone successfully connected Arduino Nano Iot 33 to AWS using SSL and MQTT? If so, how did you get the certificates (i think only 1 is need on the board) on the board?"
Thanks for your help