You said it. “My first official act as President will be to nuke Hanoi out of existence”.
After turning Hanoi into a bright, shining parking lot, I’d start carpet nuking every square mile of North Vietnam until I got to so-called “Ho chi Minh City”, and then demand they turn over all surviving guards to the Hanoi Hilton. After they do that, continue the attack until you hit the South China Sea.