Chains is in preliminary baby steps and the effects available have been hand-created to work. If your effect isn’t in that list, it may have to wait for more development. At current, there’s no way to create your own chain – that I know of. Audacity will not script.
There’s no shortage of people wanting to turn Audacity loose and come back later in the week to collect the finished sound files.
Unfortunately, the Amplify effect is not so useful in Chains, as it merely stores the amplification factor and does not adjust itself with each application of the chain. The Normalize command may be more appropriate as it always calculates the amplification factor needed to meet maximum peak amplitude. Normalize does, however, treat each channel of a stereo track separately. This is rarely an issue, but in extreme cases can alter the stereo balance of a track.
I’m not sure that having a Chain that simply calls the Normalize command would save any time unless you combine it with an export step in order to batch process a bunch of files.