For the Brussels sprouts: Place a large saute pan over medium-high heat. Add the oil and heat until shimmering. Add the Brussels sprouts, season with salt and pepper and cook, stirring occasionally, until wilted and browned in spots, 5 to 7 minutes. Remove from the heat.
For the sausage: Add the oil to a saute pan and heat over medium-high heat until shimmering. Crumble the sausage into the pan. Add the salt, sage, chipotle chile powder and allspice and cook, breaking apart the sausage with a spatula, until browned, about 8 minutes. Remove from the heat.
For the apple pico: Combine the pickled jalapeno brine with the apples in a bowl. Stir in the cilantro.
For the nachos: Spread half of the chips in an even layer on a serving platter. Sprinkle half of the sausage over the chips. Pour half of the Squasho Cheese Sauce over the sausage and chips. Top with the remaining chips, then the remaining sausage and cheese sauce.
Top with the black beans and Brussels sprouts. Spoon the apple pico over the nachos and serve immediately.
Squasho Cheese Sauce:
Toss the cheeses with the cornstarch in a large mixing bowl. Place a large saucepan over medium heat. Add the butter and melt. Add the squash, chipotle chile powder and salt. Cook until the squash caramelizes a bit, about 5 minutes. Add 1 cup water, cover and bring to a simmer. Simmer until very tender, another 10 minutes. Remove from the heat, add the milk and use an immersion blender to blend until silky and smooth. Add the cheese mixture, return to the heat and cook, whisking, until the cheese melts, 5 to 7 minutes. Season with additional salt as needed.
Squasho Cheese Sauce recipe courtesy of Jeff Mauro