We don't recommend using home made laundry soaps/sodas or powders for very good reasons! However, no one says it as clearly as the guru's over at Fluff Love University. Check out thier article on washing sodas/soaps and homemase producsts for more info:
Nellies is not a good detergent to use for cleaning cloth diapers. We highly recommend commercially available detergents like Tide original because of it's proven cleaning power!
If you are ever in doubt whether your detergent is safe to use with cloth diapers or not you can check on Fluff Love University's detergent index! They have done all the research for you:
They have a huge list of laundry detergents they have tested and know are safe for cloth diapers and what amount to use!