Royce Nama chocolate is like a semi ganache/truffle style chocolate. My coworkers request this when I go to Japan There is one flavor which is alcohol free. You can get it in the states for double the price if you are lucky to live near one of the resellers or willing to pay for expedited shipping since it needs to be chilled. The regular two flavor box of individually wrapped chocolates is also pretty good and great for sharing. The chocolate covered potato chips aren’t worth the packing space, IMO.

Anime convention goers are pretty familiar with pocky, kit kat, and ramune. We can get pocky and chocolate pandas at our N. Cal Costco. Wouldn’t be too surprised if there isn’t a more Asian food Costco in Seattle...

Mintia mints come in a clever dispenser and she might like a few packs from a convenience store. Calbee sells a lot of salty snacks including potato sticks. My old school favorite is still their shrimp chips.

ETA: You might see small bags of little candy stars at some of the airside stores. They’re kind of associated with a Studio Ghibli movie and also an old fashioned candy. It is basically solid colored sugar and the cute mini bag is marked up for tourism. If you ever get to Tokyo, there’s an “Okashi” chain shop “Niki no Kashi” which has a huge store in Ueno. It is snack paradise and has all the okashi in loose singles (downstairs) or bulk (upstairs).