(it's) no biggie

:  that one — compare he, its, she, they

: used as subject of an impersonal verb that expresses a condition or action without reference to an agent

: used with many verbs as a direct object with little or no meaning

:  the player in a game who performs the principal action of the game (such as trying to find others in hide-and-seek)

:  one that is big and often important