I copied this from Nathan's own Myspace bio...hope this helps clear up the confusion.

NATHAN PACHECO

A Washington DC native of Brazilian descent Nathan is an opera trained tenor who sings with the warmth of the great pop artists. Nathan expresses his love of languages by writing lyrics in Italian, Portuguese and Spanish with the passion of a poet. “ I sing from my heart,” says Pacheco. “Because that’s the way they do it in Brazil.” “As a singer and writer, I couldn’t wish for a better opportunity because Yanni’s music has so much emotion and my singing style requires that kind of feeling.”

Thanks for the info Linda and Nsh.Nightingale.
As I said there's a difference between tenor voices and baritone voices...The range and the timbre are completely different..for example a baritone voice is more intense and "mature"(I don't know how to explain it in English..).I know the difference between tenors and baritones very well..( not only because my Dad is a baritone,but also because I've had the chance to hear some of the best Opera singers in my life..).

I've listened to Nathan's voice..and he's a tenor,not a baritone.

Myky