Chins should not have any fruits or vegetables at all, both are too high in sugar, which chins can't process well (there is already enough sugar in the pellets). In addition they should not have any seeds or nuts, both are too high in fats, and no animal products (milk, eggs, meat, bone, etc), chins are grass herbivores.
Good treats for chins are, a Cheerio, a piece of a Shreddie, a few pieces of slow cook oats, a rosehip, a few rose petals, as well as other herbs like those sold on
Fuzzies Kingdom, serving suggestions are on the website. With the cereal it's best to stick with about once a week, the herbs though can generally be given every day. However stick to one treat per day max. If you want to give more treats, for training or something, use wood chew sticks or a different kind of hay then you normally feed to hand the chin instead.
You didn't mention hay, hopefully you just didn't mention it but feed it, chins should have unlimited hay every day. The most balanced hay is timothy, but other kinds are good too for variety of flavor and texture.