here we go again. both annunciations are correct however...
http://dictionary.reference.com/browse/niche
Dictionary.com declares only one way 'NITCH'
American Heritage and Merriam-Webster both claim both methods are acceptable. however MW, long considered the authority on the matter of the 3 above mentioned sources... claims that 'nEsh' or 'neesh' is a "sometimes" used alternative. thus making people using 'nEsh' the minority.
Logical reasoning would thus lead me to conclude(in a black/white world) that if only one party can be correct it would be those saying 'NITCH'! Based on the fact that they are the majority.
so ha, fucking ha ha ha you dirty Canadians, sucks to be out numbered.