the previews they showed last week kind of gave it away. The designer dress shirt with the sleeve rolled up, the gold watch, the thick italian arm hair. I thought that was so obviously Nathan.
Bigger shocker (although this was from last week): George Takai (a.k.a. Mr. SULU!) at Hiro's father! That was just so completely appropriate, especially considering that Star Trek quotes were among Hiro's first lines of the entire series.
If somehow his mother was Lt. Uhura...