Cut chicken breast into small cubes or strips. Clean and wash vegetables. Cut broccoli into bite-sized pieces and cut carrots into strips. Pat spinach dry with a kitchen towel and cut spring onions into rings.
Heat sesame oil in a wok over medium-high heat. Add chicken and spring onions, fry for 3-4 minutes until chicken is no longer pink on the outside. Add broccoli, carrots, and spinach, stir and cook for 2-3 minutes.
Pour in coconut milk. Add instant vegetable stock, chili powder, salt, lemon pepper, and turmeric to taste. Stir well to combine, then add sauce thickener to desired consistency. Simmer for 8-10 minutes until chicken reaches 74°C/165°F internally and vegetables are tender-crisp.