Not built-in, but you can download Fisher's exact test with n x m contingency table from the File Exchange. The Comments indicate that it doesn’t calculate the p-value, but that calculation appears to be available at the linked-to MathWorld article on Fisher's Exact Test. However, that does not appear to be trivial, and could be computationally intractable considering the factorials involved.
There is probably a good reason Fisher’s Exact Test is usually restricted to 2x2 tables with low numbers of observations. It is most accurate in that instance, and the computations are tractable.
It is probably better to go with the Chi-Squared test if you have more categories and a large number of observations.
