Nilsen has won several awards for his design work, including the Norwegian Design Award in 1986 for his "Harmony" chair, and the Northern Norway Design Award in 1991 for his aluminum garden furniture. He is known for his minimalist, functional style, which emphasizes the quality of materials and simplicity of form.
Today, Torstein Nilsen is considered one of Norway's most influential designers. His creations are exhibited in museums and galleries around the world, and he continues to work as a freelance designer from his studio in Oslo.