Heat the oven to 400 degrees F. In a medium bowl, toss the chickpeas with 2 teaspoons vegetable oil, salt, and spices. Transfer to a baking sheet and roast, stirring occasionally, until browned and crispy, 40 to 50 minutes. Once crisped, set aside until serving.
While the chickpeas roast, start the soup: Heat 2 tablespoons olive oil in a large pot over medium heat. When hot, add the spices and stir until fragrant, about 1 minute. Then, add the carrots, leeks, and garlic and cook, stirring often, until soft, 5 to 7 minutes.
Pour in the chicken stock, coconut milk, and 2 cups water and bring to a boil, scraping up any brown bits on the bottom of the pot. Reduce heat to a simmer. Taste and add salt as needed.
Add chicken breasts to pot and simmer until cooked through, about 10 minutes. Remove from pot and shred meat, using two forks. Stir in chickpea noodles and cook until al dente, 8 to 9 minutes.
In the last 2 minutes of the pasta cooking, add the shredded chicken and most of the cabbage to the soup. Taste and add salt as needed. Divide into bowls, then top with crispy chickpeas, cilantro, and remaining cabbage.