In a medium bowl, mix graham cracker crumbs, sugar, and melted butter. Press into the bottom of a 9-inch springform pan. Bake for 10 minutes, then set aside to cool.
In another bowl, mix coconut milk and chia seeds. Set aside for 5 minutes to allow the seeds to soak.
In a large mixing bowl, beat cream cheese until smooth. Add sugar and vanilla extract, beating until well-blended. Add coconut milk-chia mixture and beat until just combined.
Pour filling over cooled graham cracker crust. Bake for 45-50 minutes. The center may jiggle slightly when done, but the edges should be set.
Cool completely at room temperature, then transfer to the refrigerator to chill for at least 2 hours or overnight.
For the topping, whip heavy cream and powdered sugar until stiff peaks form. Spread over chilled cheesecake and top with fresh mixed berries.