Ice Cube -- Derek Fisher's My 2nd Choice ... For Lakers Coach

Despite having no head coaching experience whatsoever, Derek Fisher has Ice Cube's blessing to be the next coach of the Los Angeles Lakers ... but only if his 1st choice falls through.

Our photog spotted Cube in New York City on Tuesday (yes, he leaves L.A. sometimes) where he said he's cool with Fisher pulling a Jason Kidd ... retiring and then immediately coaching.