How do you write an entire opinion about delegation without mentioning Chevron? As the dissent points out, that delegation is inherently required to do the EPA's job and the court has previously accepted their technical and policy expertise in this area.
You would think they would have reversed Chevron, or distinguished it. But note, I've not read this decision yet, and I'm taking your word for their not mentioning Chevron.
I wonder if the conservative majority will use these recent decisions as precedent to overturn Chevron in what would be another shocking and shameless display of legislating from the bench.