That’d be possible - supposing there’s sufficient BTC/USD liquidity.
That’s one of the reasons why it’s hard to attract liquidity to those pools.
If it’s ever necessary for Nu to support NBT/USD pairs by funding operations (obviously directly only possible with NBT; USD had to be deposited as BTC and converted) and Nu can live with USD sitting on the account for some time, count me in (as long as AML/KYC doesn’t apply to trading USD pairs)!