The plastic under cover is easy and quick to remove/replace. The ground straps are a total of 4 bolts to remove/replace. If they do all the disconnecting and testing, it might take longer than 1/2 hour (but not much). You might be able to see the new ground plates (and bolts) with a mirror and flashlight if you want to confirm the repair. According to the inspection/repair procedure, the flat rate time that Nissan reimburses the dealer is 1.1 hours.
Silver LEAF 2011 SL rear ended (totaled) by in-attentive driver 1/4/2015 at 50,422 miles
Silver LEAF 2015 SL purchased 2/7/2015; traded 8/10/2019 at 82,436 miles
White LEAF 2019 SL Plus purchased 8/10/2019