Final answer:
Kazuya Nakai is the Japanese voice actor who often shares roles with J. Michael Tatum due to the similarity in their voices, with characters like Roronoa Zoro and Erwin Smith as examples.
Step-by-step explanation:
The Japanese voice actor (VA) known for having a similar voice to J. Michael Tatum, often leading to them being cast in the same roles, is Kazuya Nakai. This is a common occurrence in the voice acting industry, where a particular tone or quality of voice is needed to match a character across different languages. Nakai is known for his deep, smooth voice which resonates similarly to Tatum's baritone, making them a perfect match for characters in anime dubbing. Some of their shared roles include characters such as Roronoa Zoro from One Piece and Erwin Smith from Attack on Titan.