Make the crust: Combine all crust ingredients in a food processor. Process until evenly blended; crumbs should be completely moistened by the butter. Spread the mixture evenly on the bottom and sides of a 12-cup mini muffin tin. Bake crust at 350°F for 8-10 minutes. Allow to cool thoroughly before filling.
Prepare the filling: Whisk together sweetened condensed milk and eggs. Slowly whisk in Key lime juice. Spoon filling into cooked tart crusts. Bake at 325°F for 10-15 minutes. Be careful not to overbake. Chill to set for a minimum of 2 hours.
Prepare the topping: Mix together the topping ingredients. Spread evenly and smoothly over each tart.
Make the Chantilly cream: Place the heavy cream in a mixer bowl with the whisk attachment. Whip the cream on HIGH speed until whip marks are visible (soft peak stage). Add the vanilla and powdered sugar. Continue mixing until product is firm enough to hold a form (stiff peak stage).
Dollop cream over each tart. Sprinkle with lime zest and garnish with pecans.