Question

Is there a second less than a nano second

Answer 1

One second is greater than that of one nano second.

Because nano second is a very small unit.
A nanosecond (ns) is an SI unit of time equal to one thousand-millionth of a second (or one billionth of a second), that is, 1/1,000,000,000 of a second, or 10^−9seconds.

That is a second is greater than one nano second.