Im Just Gonna Act Like Gojo Never Died I Can’t Cope Still - Blog Posts

Who Nanami saw before his death:

Nanami's reaction:

Who Gojo saw before his death:

Gojo's reaction:

Gege made it canon that after death you meet your special person to comfort you. I love he showed this in the manga.

Even if the whole 236 chapter was just Gojo's hallucination before dying, consider Nanami's words when he said: "Thanks to Haibara it wasn't that bad."

This would mean, that Gojo hallucinated Geto for his own comfort before dying. After everything, Geto was still the only person he wanted to see by his side.