If you need to get some international/western food such as some pasta, beer from Europe, or even Korean noodles/snacks, one of the best places to go in Chiang Mai is Rimping supermarket. They have about 6 different locations throughout different parts of Chiang Mai (including one inside MAYA mall near Nimmanhaemin Rd.) and they have great selection of freshly baked bread (I get the baguette every morning for my sandwiches which is baked fresh every morning but make sure to go before noon as they sell out quick and they don’t make them in the afternoons), fresh fruits, and fresh meat if you like to barbeque your own steaks.
You can also find many American/international household items.
They have great selection of ham, prosciutto, sausages from Europe and locally made. My favorite is the spicy Bangkok Ham, which is ham with Thai peppers inside, makes great for spicy sandwiches, I eat it like every day it’s so good.
Cheese selection is also very good, they sell all types of cheese from Europe and locally made to satisfy your cheesy appetite. I usually pick up a few blocks of mozzarella cheese and shred my own for making pizza at home. They do sell shredded mozzarella too but they are usually not fresh and best to buy blocks as it’s also much cheaper.
For pizza dough, you can make your own dough or you can grab the mediterranean frozen all-purpose dough.
Pet food? Yes, I grabbed a bunch of dog food for my dog here, they mostly got Pedigree for American brand but they have enough selection to keep your pets happy.
If you are into fish, you can find great selection of fish here also.
Want to cook your own steaks at home? No worries, grab fresh beef just like in America. Prices are not bad considering dollar goes a long ways recently in Thailand.
Of course, if you love fruit like durian or any local Thai fruit, Rimping sells the most fresh fruit. Even local Thais prefer buying them at Rimping due to freshness. I can’t stand the gaseous smell of durian back at home in the U.S. but durian in Thailand is super fresh, there’s zero gaseous smell and surprisingly now I enjoy eating durian.
Of course, all Thai groceries and 7-11 have selling hours for alcohol. You can only buy alcohol between 11AM to 2PM or 5PM to midnight. Best way is to always get more alcohol than you need in case next time you get stuck at 2AM needing to get some and finding you can’t buy it.
And also be aware of Buddhist Day, the day you cannot buy any alcohol during that whole day! It happened to me once a few years ago in Bangkok and I had the most sober day of my life. It doesn’t mean you can’t drink alcohol that day, they just don’t sell any so just stock up the day before and you should be fine.