Career
Nillson started his career at and made his Allsvenskan debut at seventeen years of age. In the middle of his career he moved to Gislaved because of his work and took up playing with local team Gislaveds Instruction Section. He was later convinced to move to Halmstad to play for Instruction Section Halmia which he did until 1964 when he returned to During his career he also played six times for Sweden, he earned the first cap at nineteen years of age.
Bertil Nilsson is the son of former player and manager Sven Nilsson.
His father also earned a cap for Sweden.