Heat the olive oil in a skillet over medium-high heat. Stir in the curry powder, jerk seasoning, bouillon granules, onions, and garlic. Stir and cook for 2 minutes.
Reduce heat to medium, add the chicken, and continue to stir and cook 6 to 8 minutes more. Stir in the squash and mushrooms. Reserve 1 tablespoon green onions for garnish, and stir in the remaining amount. Continue to stir and cook 2 minutes more. Pour in the coconut milk, tomatoes, 1/2 cup reserved tomato juice, and sugar. Reduce heat to low, and simmer for 35 to 40 minutes, stirring occasionally. Serve, using 1 tablespoon green onions for garnish.