Preheat the oven to 450°F.

Place a large skillet over medium-high heat, add the sausage, and cook until it is nicely browned and the fat is rendered, about 5 minutes. Use a slotted spoon to transfer the sausage to a paper towel–lined plate to drain.

Add the green onion bottoms and the garlic to the fat remaining in the skillet, and cook until fragrant and soft, about 20 seconds. Add the beans, mix well, and cook until heated through, about 1 minute. Add the chicken stock, chili powder, cumin, and salt.

Mash the beans with the back of a heavy wooden spoon or a potato masher until chunky-smooth.

Reduce the heat to medium and continue cooking until completely warmed through, 1 to 2 minutes. Remove from the heat.

Spread half of the tortilla chips in one even layer on a large oval ovenproof platter or in a large baking dish. Top with half of the beans, half of the sausage, half of the cheese, and half of the jalapeños. Repeat with another layer of chips, beans, sausage, cheese, and jalapeños. Bake until the cheese is melted and the mixture is hot, 2 to 3 minutes.

Remove from the oven, and serve garnished with chopped green onion tops, salsa, and sour cream.