This is poor reporting by the Disney blogs on a NYT article with one poor line.
When Iger stepped down as CEO, he assigned himself the new role of Executive Chairman. This position is different from Chairman of the Board, as it's still an executive position. This means that from the day Chapek started as CEO, he reported directly to Bob Iger, who had more authority than Chapek when it came to running the company.
The announced plan from that very day was for Iger to continue to steer the ship for the next two years while Chapek got up to speed with CEO duties, so that at the end of 2021 Iger could resign from Exec Chairman and let Chapek truly run things, answering only to the board in the way any CEO has to answer to a board.
In other words, the powers Iger has today are the same powers he had a week ago and the first day he wasn't CEO. More importantly, he's literally not taking back the position as CEO.
The NYT article has one line in it that implies he's "effectively" running the company, even though that was his stated intention from day one. The longer and more accurate takeaway should be "Iger filling the exact role he outlined when he stepped down as CEO, it's just more important now than before because the company is financially struggling from the pandemic".