NAND gates are enough to computer any boolean function. Being Turing complete requires some notion of state and state transition. However, a RAM machine where

NAND gates are enough to computer any boolean function. Being Turing complete requires some notion of state and state transition. However, a RAM machine where the program counter is memory mapped, can be Turing complete with a [single machine instruction]( https://en.m.wikipedia.org/wiki/One-instruction_set_computer https://en.m.wikipedia.org/wiki/One-instruction_set_computer).