I use hard candies for lows. 3 regular peppermints are 15 carbs. For quick portable snacks, I like the packs of PB crackers, Nature Valley Crunchy granola bars, and the packs of 100 calorie cookies/crackers which mostly seem to be 14-17 carbs, depending on the type/brand. To add a little protein, I’ll eat a string cheese. I’ve carried them around for several hours before eating them, and they don’t go bad or anything. Just make sure they’re refrigerated if you end up not eating them. Cheese is more flavorful and is supposed to be served at room temp anyway. If you can eat an apple or pear, that’s a good choice too. The fiber modulates carb absorption.
I love chocolate too. I used to try and buy the bags of minis/snack size, but I’d end up eating half the bag, completely defeating the purpose. Now I buy regular sized chocolate bars. I keep them in the fridge, and I have one maybe once a week. There was a time when I wouldn’t have been able to even manage that - I would’ve eaten however many I had all in one sitting - but now I’m able to just have my one treat and be satisfied.