How to run certain scripts/commands after stack creation

Hi all,
I need to run several commands/scripts after the stack has been completed, but with values from my constructs. I stumbled upon this piece of code

const nullResource = new Null.Resource(this, "buildAndPush", {
  triggers: {
    foo: 'bar'
  },
});

nullResource.addOverride("provisioner.local-exec.command", 'az keyvault secret set --name .....');

but for what ever reason it does not get executed properly.

Any hints?

Regards
Mathias

Ok, solved, was some issue with the trigger