Nanomech is about an inch tall at full size. He has blue skin with a green circuit like design on it. Nanomech possesses green wings and as well as one large, green cyclopean-eye. He is composed of carbon/silicon-based mechanical body and has triangular feet. From a normal sized perspective, when Nanomech speaks, he has a squeaky little voice, but from anything of his size's perspective, his voice is very deep.
In Omniverse Nanomech's circuit design is gone, being replaced with a design pushing more to his Alien Swarm design, and the Omnitrix symbol is where his eye was. He has different wings, he speaks with a more robotic tone, but still high-pitched.
Nanomech has the ability to fly, fire green energy balls from his hands and shoot green lasers from his eye. He can also shrink to microscopic size. He can return to his normal size, but can't grow any bigger. Nanomech’s wings glow when he flies. He is also extremely agile.