One way is shorting the two inputs of the NAND gate and passing the input.

truth table:

A B output

1 1 0

0 0 1

The second way is passing the input to only one input(say A) of the NAND gate.Since the other input(say B) is floating, it is always logic one.

truth table:

A B output

1 1 0

0 1 1