No, corn is not safe for chins so cereal made of corn is also not safe. They also have about 3 times as much sugar then cheerios.
Cheerios (and other cereal) really aren't advised as treats anymore (like within the last couple years). Studies have come out that the name brand ones test high for cancer causing chemicals (chemicals used on commercial crops), but even if you only get 100% organic ones they still should be given very sparingly if you choose to give them at all. They are gassy so you do risk causing gas and bloat, which can be fatal in chins, so it's best to keep gas drops on hand just in case. I can give you a list of most updated recommended safe treats of you want.