Run MultiBeast and you can install Chimera from there. Be sure to read the description found on the bottom of the interface, as it will tell you what is going to be installed (or changed) for each step. If your motherboard had a DSDT file in the database here on the site, then you can select the UserDSDT the option, which will also install Chimera as well. Finally, make sure you select the Repair Permissions check box in MultiBeast so that your changes stick.
Once you install Chimera, you should not longer need to boot with the installer USB stick anymore.
TB