Repealing and overturning are two completely different things done by two completely different branches of government.

The overturning of chevron now allows the federal courts to prevent the HHS and CMS from doing their jobs which can prevent the Affordable Care Act from being carried out effectively. Once it's no longer functioning the republicans will have a much easier time overturning it without massive backlash from the American public who overwhelmingly support it (most importantly without pissing off the independent vote).