Well for now since you don't have livestock, maybe you could wait a little bit for your cycle to finish, then add corals into your main tank. If you start another tank, you'll have to cycle it too. Or, to speed up your cycle on your secondary tank, you could add substrate and pieces of live rock from your main tank into the nursery, and water from the first tank. It will cycle faster..but don't add stuff right away, you'll have nitrates from the 1st tank's water.
My friend started an independant nursery system..with 2 x 10 gallons rubbermaid + sump + caulpera in sump + giesemann 150 w HQI 20000k.
It works, and he did what i just suggested you. BUT..his main tank is nitrites/ammonia/nitrates free, AND 2 years old.