In a food processor or blender, grind gingersnaps until fine. Pour into a bowl and stir in pecans, melted butter, brown sugar and salt. Press bottom and sides of a 10-inch springform pan. Refrigerate 30 minutes.
Beat the cream cheese in a stand mixer until soft, scraping the sides once. Mix in pumpkin, scraping sides once or twice. Add eggs one at a time, allowing them to mix in, then add sour cream and mix.
With mixer on low, add granulated sugar, cinnamon, vanilla and nutmeg. Thoroughlyscrape bowl and mix to ensure everything is smooth and mixed together.
Pour filling into the pan, smoothing the top. Set pan on a baking sheet and bake at 350° until the filling is no longer soupy but still slightly jiggly, about 50 minutes.
Turn off oven, slightly open the door and let the cheesecake sit in the oven for 15 more minutes. Remove from oven and allow to cool for 30 minutes, then cover with plastic wrap and place into fridge to chill for at least 4 hours or overnight.