It’s my understanding that you are using Naïve Bayes classification for a multiclass problem with fitcnb function, and want to try some other distribution apart from Normal Distribution.
You can use Multinomial Distribution, Multivariate Multinomial Distribution, Normal Distribution. To use these, you must specify them as
Mdl = fitcnb(___,Name,Value) ;
Name will be ‘DistributionNames’, and
Value can be ‘mn’ (for Multinomial Distribution), ‘mvmn’ (for Multivariate Multinomial Distribution), ‘normal’ (for Normal Distribution).