Based on what you've described you have a Nominal or Ordinal column in both X and Y. Since JMP tries to steer you away from common statistical mistakes it will not show you tests that aren't appropriate for the data you have provided. So you don't have a Kruskal Wallis test because it's not appropriate for the comparison you are considering.
If you look closely at the bottom of the Fit Y by X platform (Analyze > Fit Y by X - second image), you will see a table that shows what combinations of variables will give which reports. For the non-parametric comparisons, you need to have a continuous Y and a categorical X (this gives the Oneway platform).
Examples of reportsThe Fit Y by X dialog
So, if you want to examine the number of people in a particular category you would put your patients in Y and grouping variable in X. I'm hoping these are average patient counts and not actual patient counts. There is an argument to be made about treating patient counts as a continuous variable - but that's probably a different post.
Here is the link to the documentation on the platform (just so you have it ready to hand): https://www.jmp.com/support/help/13-2/Introduction_to_Fit_Y_by_X.shtml#
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