Heat a large wok or large skillet over high heat. Add 1 tablespoon oil; swirl to coat. Add lemongrass and garlic; stir-fry 30 seconds. Remove from pan with a slotted spoon; place in a small bowl. Add bell pepper, shallots, and haricots verts to pan; stir-fry 2 minutes. Remove vegetables from pan with a slotted spoon; add to lemongrass mixture. Add remaining 1 tablespoon oil to pan; swirl to coat. Add chicken in a single layer; cook 2 minutes or until browned. Add cashews and chile to pan; stir-fry 2 minutes or until chicken is done. Stir in stock mixture and vegetable mixture. Bring to a boil; cook 1 minute or until sauce begins to thicken. Serve immediately.