Madison won the Oscar for her first major big-screen leading role ... with only A Complete Unknown and Nickel Boys going home empty-handed.

At Sunday night's Oscars, there was one big winner, a lot of heartfelt speeches ... nominees — all but A Complete Unknown and Nickel Boys — went home with something. Mikey Madison poses ...

Ahead of the Oscars, O'Brien told "Good Morning America" that he was enjoying the preparation for the big show.