Narayana means the final goal of all human beings and it is also the name of Lord Vishnu as per ancient Vedic texts. Hence, Lord Vishnu and Narayana are the same. Their name also refers to God in his infinite form and implies the one who rests on the water.
In the same essence, Lord Vishnu has more than 1000 names and he is known by more than one name.
As per Vedas and Upanishads, these names refer to the supreme lord or the Parmatama.
Krishna is an avatar of Lord Vishnu and the Narayana is the part of the half of Nara-Narayana.