Yes, but you have to pay for the power plant, and being just a bit over unity won't cover the expense of the next stage in the chain.

You have to be enough over unity to pay for another plant plus surplus to actually use. In which case you can just build a bunch of plants - you don't need to chain them. There are plenty of other power sources you can use to bootstart the power plants.

Even regular power plants need power to start them see https://en.wikipedia.org/wiki/Black_start