Oil the sides of an 8-inch springform pan and line the bottom with a circle of parchment paper.
Pulse the pecans in a food processor until crumbly. Add the remaining crust ingredients and pulse just until combined. Mixture should be crumbly.
Wet your fingers or use a spatula to press the nut mixture evenly into the bottom of the prepared pan. Place in the freezer to set while you prepare the Chocolate Avocado Mousse filling.
Peel the avocados, remove the seeds and scoop out the flesh. Place all mousse ingredients except the chocolate chips in a clean food processor and process until smooth.
Melt the chocolate chips, add to the food processor bowl and blend until smooth.
Remove the crust from the freezer, scoop the mousse filling on top and smooth it to the edges of the pan. Return to freezer for 2 hours to set.
When thoroughly chilled and set, remove from freezer and let it sit for 5 to 10 minutes before serving chilled. Top with fresh berries, if desired. The torte will soften at room temperature, so wrap any leftovers tightly and return to freezer.