Nilsson is being awarded for a "profound and long-lasting impact on Swedish music life, especially in the field of electroacoustic music".
The 86-year-old pianist, organist and composer is considered one of the pioneers of electronic music in Sweden.
"Throughout his entire artistic life, he has, with tradition at his back, worked to break new ground both artistically and technically," writes the jury.
The Composer's Prize, established in 2017, is one of the Royal Swedish Academy of Music's finest awards. It is awarded every two years for "significant work as a composer". The prize money is 100,000 kronor.
The prize will be presented by the King on November 24.
