As you probably know, you're replacing the fix you got with nicotine with food. Exercise is extremely important in a quit imo. It helps address the extra anxiety/stress you are experiencing, keeps weight gain at bay, and just makes you feel better overall. I am doing a strength gaining program (5x5) during mine, so at least some of those extra cals are going toward muscle. I've only gone up from 205 to about 215 and now back down to 211 or so and I'm significantly stronger than when I started (about 75 days ago).
Anyway, it's better to eat something than to cave but try to keep it in check. Also, keep better alternatives around (gum, seeds, toothpicks) versus sweets and other high carb/fat shit. If you want info on 5x5 or nutrition/exercise/etc let me know.