Nikolaevich is a common Russian patronymic, a middle name formed from a father's first name, in this case Nikolai. As a standalone clip it has no clear credited source, so its life online comes from reuse rather than a known scene. Short name callouts like this spread on soundboards because they are instantly reusable, easy to recognise after one play, and funny out of context. Creators keep using it as a mock formal summons, a reaction to being in trouble, or a random non sequitur in edits and chats.