Right now, there isn’t any confirmation about his return. As it is, his version of Green Goblin died in Spider-Man in 2002. Willem returned for the other two movies in the Tobey Maguire trilogy, appearing in Green Goblin’s son Harry’s hallucinations.
All is not lost, though. Even if no one attached to Spider-Man: No Way Home confirmed Willem’s return, he hasn’t outright denied it himself just yet.
In an August 2021 interview with The Wrap, Willem deflected questions which asked about his Spider-Man return.
“I got lots of stuff happening now. And, you know, I always feel like when a film comes out, that’s when it’s time to talk about it,” he said at the time.
He also said that “no comment” was his official stance on questions about his return as Green Goblin.
So you’re saying there’s a chance.