Issue uploading avatar with no chest bone

Hello. I’m currently kit-bashing an avatar which has a base model rig without a chest bone. The model looks great in LIV but I was hoping to upload it (or a modified version) to VRchat as well. Any advice on how to properly add a chest bone? I’m pretty noob with rigging but have been reading and watching some videos. I’m a little confused about the purpose of the chest bone and if I’m parenting them properly.