1st to get chocolates you have to probably visit howard's cafe on the days like harmony
day and stuff and he will probably have it. 2nd to ask someone to go starry night festival
with you-you have to at least have idk like 2-3 flowers bloomed with them (guess i had 3
when i asked ash) and then visit them the day before starry night festival and talk to
them a few times and then they will actually ask u to go instead (well i think.. ) so
thats it...

I'm pretty sure you have to buy a cocoa sapling from the guy in konohana, plant it,
harvest the cocoa and cook it in some way to make chocolates. If you're looking to get
chocolate for the pumpkin festival, you don't need chocolate, you can make any dessert and
give it to the kids.