| Nathan is one of three actors to cross over and play a Big Bad on either Buffy the Vampire Slayer or Angel after Firefly was cancelled. He played Caleb, the evil preacher, in Season 7 of Buffy the vampire Slayer. |
| In 1996, Nathan was nominated for a Daytime Emmy Award in the category of Outstanding Young Actor. |
| Nathan is the voice for Gao the Lesser in the video game Jade Empire. |
| Nathan has blue eyes. |
| Nathan has a tattoo of an Egyptian glyph on his right hip. |
| Nathan moved to New York City in 1994. |
| Nathan auditioned for the role of Angel on Buffy the Vampire Slayer, but Joss Whedon didn't remember him when casting him in the role of Malcolm Reynolds on Firefly. |
| In 2005, Nathan starred in the James Gunn horror film, Slither, as Bill Pardy. |
| Regarding his role as Caleb, Nathan said: "What I enjoyed about playing Caleb was that he was so very, very clever, so very, very sweet, and so very, very twisted." |
| In college, Nathan majored in art and minored in drama. |
| Nathan had corrective eye surgery when he was 12 years old. |