sorry i must have missed that, the 12 gallon nano doesnt NEED a skimmer, but i highly recommend it. An AquaC remora nano skimmer is the best nano skimmer on the market, stay away from the fission nano skimmer. With a skimmer it will be a bit easier to keep nitrate levels down.
96 watts is not enough for most corals, go with an MH that has 2 150 watts and then add either T5 actinic or PC actinics.
Dont really need to add any chemicals in your tank, the good quality salt mix should have it all in there.