Nanotechnology do not essentially increase life span. What control our life span is aging. With the cells aged, cancerous cells are easier to surface. You can prolong your life span if you can control the aging process. People do die even though they do not sick or having any form of cancer. They organs aged and failed after their supposed life span.

Everything fails, but our body fails after 60-70 years of continuous usage (compared to some mechanical part which lasted 10 - 20 years only). Isn't it good enough?