This video says it was going to be launched in May 1991. https://www.youtube.com/watch?v=2GSqc4mjh2o

@Tristen Timberwolf Yep, it was developed before/along with the SNES version and was meant to be released on Spring 1991. Even mentioned a few times on the old Nintendo Power magazine. It was planning to be US only (maybe Europe too but Infogrames did have the rights to the game for the region at the time hence Amstrad/Spectrum versions, it would have cleared up by release as unlike the US SimCity SNES, it was not a launch title in PAL regions).

It got cancelled for the SNES version and the version that got dumped was the last known version, still unfinished. Seemed that the reaction at CES was what might caused it to pull out...

Didnt know there was going to be an nes version