I hate leaving food too. I feel bad and I tend to over eat because of that when I go out to a restaurant. Lucky for me I don't get to go out very frequently.
Haha aww it's no problem. Since I really don't know what you like and what you don't like I can only offer suggestions.
If you like rice I would suggest making a couple of onigiri. Or you could always do a stir fry of rice. If you're not a fan of it or do not have japanese style short grain rice you can make noodles and top them with the chicken. Depending on what you like to flavor your noodles with you can go with an asian flavor scheme and use teriyaki, stir fry, or whatever kind of sauce you like. If you like peanuts/peanut butter here is a recipe that you might like, I've had it and it's really not bad at all:
[link] If you don't like an ingredient then you can leave it out or replace it. I don't really care for red peppers so I would add something like broccoli, asparagus, corn, carrots, ect. Things that I actually like and eat.
Since I also don't know the size and shape of your bento box I can only guess on what you can and cannot fit into your box. If you have a two tier box then I would fill the top tier with the noodles/rice and chicken and the bottom with veggies and fruit or salad. If you have a single tier box then fill half with the noodle/rice/chicken mixture and the other half with veggies/fruit/salad. I would add maybe a slice of apple (soak it in salt water for a few minutes to prevent browning) and a couple of grapes. If you're don't have veggies you want to add then add a salad and pack the dressing on the side. That way it won't get all over the fruit and it won't make your lettuce soggy.
I hope that helps! I had precious few details to work with and if you have any more questions then please don't hesitate to ask me. I love helping with bento questions.