Nozzle size (aka nozzle diameter) is not actually used by any setting save the line_width. The line width has a function that uses the nozzle diameter to calculate the line width. So if the nozzle diameter is changed, the line width will change accordingly.
If you do override it for some reason, an inheritance warning icon will pop up to notify you of such a change.
Also note that for the UM2+, your profiles are stored per combination. If you create a profile, you create a profile for that nozzle. So if you switch the nozzle size in the dropdown, so will the profile.