Your approach seems pretty solid to me and I think Composition.progress_note is a better fit for ongoing documentation during an admission for all clinical progress notes not just nurses. Encounter is not wrong but feels a bit closer to a typical outpatient clinic/ GP consultation or Nurse visit. Having said that, I suspect these boundaries are a little blurred in some care-settings e.g a dialysis or chemotherapy visit and I probably would not over-rely on the Composition archetype to imply strong semantics.