That's an interesting comparison with microprocessor ALU operations. (6502 is similar to Intel but doesn't have add/subtract without carry.)
Note that the Nova uses two additional instruction bits for the carry. Thus, the Intel instruction sets use two of the 8 opcodes for add with carry and subtract with borrow/carry, but the Nova doesn't. So it should be easier for the Nova to fit in additional useful ALU instructions. (Not to mention the Nova has 16-bit instructions.)
Note that the Nova uses two additional instruction bits for the carry. Thus, the Intel instruction sets use two of the 8 opcodes for add with carry and subtract with borrow/carry, but the Nova doesn't. So it should be easier for the Nova to fit in additional useful ALU instructions. (Not to mention the Nova has 16-bit instructions.)