Nastavševs, a director at Latvian National Theater, was also awarded for best music together with composer Toms Auniņš.
Nastavševs was notably absent from the ceremony, telling that he had to rest in preparation for an upcoming play.
Jury member and theater critic Līga Ulberte told Latvian Radio Thursday that "for the jury it's a sort of a sign that the director does not consider these awards to be important."
She said that the last season in Latvian theater has been very positive, interesting and with many actor performances from which it was hard to pick the best.
Ulberte praised the triumph of the Latvian National Theater, which scooped most of the awards, saying that it had been due to a determined artistic strategy on part of the theater.
"The National Theater has for long been much more than a citadel of stiffened academic traditions – it's a searching and varied theater," said Ulberte.
Best actress: Guna Zariņa
Best actor: Egons Dombrovskis
Lifetime achievement: Olga Dreģe
Lifetime achievement: Juris Strenga