If you give an agency the power to interpret the law that congress has prescribed to the agency, the agency will almost always chose an interpretation that is in their self-interest - often leading to a corrupt (really, just an outright wrong) interpretation of the law.
It's surprising that Chevron was ever even case law. Thank goodness we have a set of justices that are actually looking to get rid of conflicts of interest and focus on an objective and conflict-free rule of law.
It seems based on the dissent liberals want to relish in giving government agencies power to interpret what they want, which is consistent with yesterday's dissent from the liberals where the liberals dissented with the SEC case where the liberals dissent stated that the SEC should be able to prosecute individuals in their own SEC-based rules with their own SEC-based court.
The court system is moving to ensure there are more checks and balances and that the law is interpreted and prosecuted in a way that has less conflict of interest.