Wow. That sucks. I don't even have a Leaf any longer and when I had a '13, the map updates were certainly not free. My former '19 Bolt (got bought back by GM at the 3 year mark, related to battery recall) didn't even have a nav system (not even an option). For maps, you had to use CarPlay or Android Auto. I used CarPlay with Apple Maps, Waze and Google Maps (I use this the least).
You could get some navigation via Moronstar but that'd a paid service but I never tried it for that.