Sad to say: I can only confirm that no USD can be deposited atm:
This was answered here: https://twitter.com/southxchange/status/646854079541604353
SouthXchange uses Nubits as a proxy of USD to trade BTC/USD, just like Poloniex uses Tether as a proxy of USD.
Nu should encourage using SouthXchange.
@desrever, @woolly_sammoth, any chance to get the southx wrapper working with the flipped pair (BTC/NBT)?
More than happy to start running ALPv2 there once wrapper is available. We can start with a high-spread NuBot as long as Nu is in rough waters.