Now the company that I bought the hardware wallet from gets nuked in a war and is gone forever.
If nuke falls on company... 
This probably means they servers will go down and you won't be able to send transactions with their official app, but I don't think anyone will care about that in nuclear war scenario.
In all other cases when company servers are not working, you can always use your generated seed words and import them in any other supported wallet, preferably hardware wallet.