I can confirm that NuBus cards *can* work in the SE/30, at least in principle. The "ExpanSE/30" expansion case interfaced via a PDS card and had 2 or 4 NuBus slots.

I don't have one, but I want one!

I'm fairly certain that the IIsi NuBus adaptor card will allow use of a NuBus card in the SE/30 motherboard, but I'll have to try it out sometime to make sure.