In standard NMOS or PMOS circuitry, both a NAND gate and a NOR gate require two transistors each (and a resistor, which is usually actually a transistor as well

In standard NMOS or PMOS circuitry, both a NAND gate and a NOR gate require two transistors each (and a resistor, which is usually actually a transistor as well). CMOS requires four transistors for both a NAND gate or a NOR gate. It's only in TTL logic, where you can have a single transistor with multiple emitters that a NAND gate uses fewer transistors.