>>4855884Since niche is a word that is directly borrowed from French, some people choose to pronounce the word using the original French pronunciation. Merriam-Webster lists both pronunciations (as well as the halfway-between pronunciation of "nish" [nJʃ]), so both are technically valid.
Phonologically speaking, there is nothing in the pronunciation "neesh" [niʃ] that is actually foreign to English, so to me it doesn't really sound off-putting. A similar example would be envelope, which many people pronounce "onvelope", a nod to the French pronunciation (though not fully faithful anyway).
