In my opinion, there doesn't appear to be much rhyme or reason to the various collocations that "spout" and "nozzle" pair with. Simply going off my experiences as a native speaker of American English, it would appear that "spout" is used more for household items "faucet spout", "teapot spout", whereas "nozzle" is used for things used outdoors/commercially, such as "gasoline pump nozzle."