Is there a way to find the nearest street address using the lat/long fields? I would like to add this as a hidden field in the survey. It would be great if it did it by a calculation instead of having to reverse geocode all the lat/longs.
Survey123 doesn't currently support determination of a street address from latitude/longitude. As you note in your question, the most efficient method to do this is to reverse geocode the addresses; this can be done after collection is complete- I think this would have essentially the same effect as what you're asking (as you mentioned the field is hidden/not user accessible).
Retrieving data ...