With a cartridge BB if the shell threads are aligned on the same axis can the cartridge be unthreaded drive side with NDS cup in place?
Most cartridge BBs have a shoulder on the drive side, which is also the side that's integral to the bearings and spindle, plus a non-shouldered left cup. Some are the opposite, and some have no shoulders. Some have two similar cups, one of which may or may not be shouldered, and then the bearing and spindle unit is a third piece.
Drive vs non-drive side is unimportant to the question you're asking. Shouldered vs non-shouldered is though. What's important is that when you're done, it's all properly torqued against each other. If there's a shouldered side, that needs to be torqued against the frame, and the non-shouldered side needs to be torqued against the main BB unit.
If what you're asking is if on a common BB with a shoulder on the drive side and the bearings and spindle integral to that piece, and an unshouldered left cup, whether you can leave the left cup untouched when you take the the main unit out, no, that's not really ideal. Unscrewing the drive side in that situation can easily rotate the NDS side out a little, such that when you reinstall the DS, proper contact with the NDS cup isn't made. Or, if it doesn't move at all, the ways things settle could cause you to be torqueing the BB against the left cup and not the shoulder against the shell. The better practice would be take out the DS, unscrew the NDS a turn, torque the DS back into the frame, then torque the NDS down properly against the DS.