Be careful how you react to a bite. If you put him away when he does it, he may learn that's a good way to ask to go back to his cage! The typical advice is to not react at all, but a GCC beak can do enough damage that it's pretty hard not to sometimes. Hoepfully he's not biting that hard.
It's my understanding that most bites occur for one of several reasons -- a young bird may just be exploring with it's beak, or trying to groom you, and get a bit carried away. Scooter did this when we first got him and we were able to fix it by very gently discouraging him when he did it, but praising him lavishly for being "a gentle bird".
Fear is another reason for biting. If you are moving too fast, or he is overwhelmed, he may be biting because of that. In that case, back off, go slower, and try to avoid provoking a bite in the first place.
Learned biting is harder to fix, so hopefully nothing has been learned yet. We easily reinforce a bite without realizing it. We may put the bird away and that may be exactly what it wants. Or we may fuss and carry on, and they enjoy the drama (they don't REALLY understand they are hurting us IMO, they just understand that what they did got a certain reaction, like putting a coin in the jukebox. Oh look, the human is dancing for me!). They can get quite bossy with this.
I have gone through phases with Scooter after I have been on travel for a few days and had a sitter in, where he acts for all the world as if he is mad at me. He will reportedly be very sweet for the sitter and then be a land shark with me. He's drawn significant blood, and it takes several days for him to settle down again. Every single thing I have tried to discourage the behavior has failed to make any impact on it, and I have never gotten any suggestions as to what causes it beyond the alarming anthropomorphic idea that he gets mad at me when I go away. How I've learned to deal with that would be a long separate post, but it boils down to avoiding getting bitten even if that means he sits in his cage for a couple of days, and offering a reward for polite behavior. But I doubt you are dealing with anything like that in such a young bird.
I'd guess either Chichi is a little overwhelmed and needs a little more space -- try to give it to him BEFORE he bites you if that's the case. Observe him and let him learn another way to signal he wants to be left alone or put back in his house. OR he's just beaking/allopreening and getting a little carried away, in which case you should be able to just gently focus him on a behavior you like more.
If this doesn't work you might start working on some training, so you have other behaviors you can distract him with, such as targeting or a trick.