To be fair, they are also different things, though there is certainly overlap...

To me, tech debt, captures the idea that we cut corners now to move faster, with the understanding that it will need to be "re-paid" and cleaned up later, otherwise we take on too much tech debt, and everyone knows too much debt is bad...

AI slop code means people feed their tasks to a model, trust it to drive the changes, they might do some cosmetic clean ups, then generate a 3 pager PR description they didn't even read themselves, then toss it over to the code reviewer, let that chump figure out what the hell I was doing while I ship 3-4 more PRs...

Technical debt is a indefinable quantity which makes it very prone to be abused to mean "I wish I could rewrite this in [insert some fashionable language, framework or coding style]".

AI slop is an easier concept to quantify. It's basically the code for which insufficient people in the organisation have a meaningful understanding of how it works or what it does.