Toast the almonds in a dry skillet over medium heat for 4 to 5 minutes, stirring often, until golden and fragrant. Let them cool completely, then roughly chop and set aside.
In a medium saucepan, whisk together the sugar, cocoa powder, and salt until no lumps remain. Slowly whisk in the coconut milk and corn syrup until completely smooth.
Cook over medium heat, whisking often, for 5 to 6 minutes, until the mixture is steaming and just starting to bubble around the edges. Remove from the heat and whisk in the chopped chocolate and vanilla until melted and glossy.
Pour the base into a bowl and press plastic wrap directly onto the surface to prevent a skin from forming. Refrigerate for at least 6 hours or overnight, until very cold.
Whisk the chilled base well (it will be thick), then pour it into an ice cream maker bowl that has been frozen for at least 24 hours. Churn for 20 to 25 minutes, until it looks like thick soft serve.
Working quickly, fold the marshmallows, toasted almonds, and chocolate chips into the churned ice cream until evenly distributed.
Spread the ice cream into a 9x5-inch loaf pan or freezer container, cover tightly, and freeze for 4 to 6 hours, until firm. Let it sit at room temperature for 10 minutes before scooping.