Rascal Flatts and Underwood announced the nominations Wednesday.
Besides top male vocalist, Paisley was nominated for album of the year for "Time Well Wasted," single of the year for "Alcohol" and song of the year, vocal event of the year and video of the year for "When I Get Where I'm Going," his hit duet with Dolly Parton.
Brooks & Dunn were nominated for entertainer of the year, top vocal duo and single of the year, song of the year and video of the year for "Believe."
First-time nominees Sugarland received nominations for album of the year for "Twice the Speed of Life," top new duo or vocal group and top vocal group of the year. They also were recognized in the single record of the year and song of the year categories for "Baby Girl."
Lead singer Jennifer Nettles received a separate nomination for vocal event of the year for her duet with Bon Jovi, "Who Says You Can't Go Home."
Members of the Academy of Country Music select the nominees and winners of the ACM awards, which will be broadcast May 23 from Las Vegas on CBS.