Heat oven to 400° F. Pierce the potatoes all over with a fork, place on a rimmed baking sheet, and bake until very tender, 50 to 60 minutes. Let cool, then halve and scoop out the flesh (discard the skins).
Reduce oven to 350° F. In a food processor, process the graham crackers until fine crumbs form. Add the butter, sugar, and ¼ teaspoon of the salt and pulse until moistened. Press the mixture into the bottom and up the sides of a 9-inch pie plate, using a straight-sided dry measuring cup to help. Place on a rimmed baking sheet and bake until dry and set, 10 to 12 minutes (if the crust puffs while baking, press it down gently). Let cool.
Wipe out the food processor and add the sweet potato flesh, condensed milk, eggs, cinnamon, ginger, nutmeg, cloves, and the remaining ¼ teaspoon of salt and process until smooth (do not overprocess). Pour the mixture into the crust and bake until set in the center, 45 to 55 minutes. Let cool completely.
Before serving, using an electric mixer, beat the cream on medium-high until soft peaks form. Gently fold in the nuts and serve with the pie.