No, N is pronounced N. There should be no ambiguity in this case as "n-cyclohexyl" would be meaningless.
Sulfamate because NH2SO3H is called sulfamic acid.
Calling it "ammonium" would not be helpful or accurate. "N" indicates, not a nitrogen-containing substituent, but a substituent on the nitrogen of the main named compound. By contrast, NaNHSO2OC6H11, if it exists, would be sodium O-cyclohexylsulfamate.