Update - a week later.
Actual comments from servicing
"Removed L/S lower dash panel and knee bar. Road test = ng. unable to isolate. Removed L/S A pillar finished and road test = ng. Removed L/S dash vent and road test =ng. removed upper and lower IP clusters and road test =ng. Removed IP assy and road test =ng. Call fix for database search. Fixs says to leave car apart and send to body shop. Technician does not want car to go to body shop. Removed cowling and road test =ng. Removed front bumper and L/F Headlamp and road test = noise gone. Isolated noise to a contact spot on the headlamp. Insulated contact point with felt tape and reinstalled headlamp and bumper. Road test ok. Reinstalled all other parts removed and road test ok. Cleared codes set during diagnosis from all systems and check operation ok."
In other words Nissan took dashboard, out. Had technician drive around to determine the rattle location. foreman technician did not take it to the body shop for inspection, instead everything was stripped out, even front bumper. down to just frame supposedly. And finally, located noise to front headlight, a pin below it was loose and was the cause of all that rattle, the sound of it reverberating into the vents. Finally had my Leaf back, a luxury compared to the rental Versa that I was given.
FYI, a recall was also updated on the car about the battery charger control.
P3227 leaf reprogram
CHARGER 296A0-3NA6A to -3NA7A
HV BATT 293A0-3NA1B to -3NA1C
Reprogram Lithium Ion Battery controller and the on board ch P32270