Nothing. That was the case with the ATF bump stock ban a few years ago - eventually it was deemed executive overreach. But, the bar for proving that was higher with Chevron in place (went to appeals, where without Chevron it could go either way in district court based on a single judge's opinion).
If you believe the government is usually wrong or often acting in bad faith, you might applaud the overturning of Chevron.
If you think the executive should be allowed to implement the often vague directives from Congress without fear of being overwhelmed in court, then you might think the overturning of Chevron will kill the government’s ability to function.
Personally, I’m not keen on the end of Chevron. But it probably isn’t going to lead to complete dysfunction either.
You don't have to think most people are murderers to make murder illegal.
If the regulator is wrong or corrupt 1% of the time, it's good that the victims have legal recourse. The existence of that recourse will also make the regulators more likely to do honest work.
