For the pumpkin gingersnap cheesecake: In a food processor or blender, grind the gingersnaps until fine. Pour into a bowl and stir in the pecans, melted butter, brown sugar and salt. Press into the bottom and sides of a 10-inch springform pan and refrigerate for 30 minutes.
Preheat the oven to 350 degrees F.
To make the filling, beat the cream cheese in a stand mixer until soft, scraping the sides once. Mix in the pumpkin, scraping the sides once or twice. Add the eggs 1 at a time, allowing them to mix in, then add the sour cream and mix. With the mixer on low, add the granulated sugar, cinnamon, vanilla and nutmeg. Thoroughly scrape the bowl and mix to ensure everything is smooth and mixed in.
Pour the filling into the pan, smoothing the top. Set the pan on a baking sheet and bake until the filling is no longer soupy but still slightly jiggly, about 50 minutes. Turn off the oven, open the door just a hair and let the cheesecake sit in the oven for 15 more minutes. Remove from the oven and allow it to cool for 30 minutes, then cover it with plastic wrap and put it in the fridge to chill for at least 4 hours or overnight.
For the salted caramel sauce: Mix the brown sugar, heavy cream, butter, vanilla and salt in a medium saucepan over medium-low to medium heat. Cook, while whisking gently, until thickened, 5 to 7 minutes. Let cool, then refrigerate until needed. Serve warm or at room temperature.
Slice the cheesecake and top with the salted caramel sauce, whipped cream and chopped pecans.