What is matthew nickname?

As an AI language model, I cannot be sure which person with the name "Matthew" you are referring to. However, here are some common nicknames associated with the name "Matthew":

1. Matt – the most common nickname for Matthew
2. Matty – a playful and affectionate variation of Matt
3. Maddy/Mattie – a feminized version of the name
4. Mateo – a Spanish variation of the name, often used interchangeably with Matthew
5. Matt-man – a more informal nickname, often used among friends
6. Matty Ice – a nickname inspired by the NFL quarterback Matt Ryan.