Squash, chicken & couscous one-pot

Name: Squash, chicken & couscous one-pot
Prep time: 15 min
Cook time: 45 min
Total time: 1 h
Cuisine: Moroccan
Ingredients: 2 tbsp harissa paste; 1 tsp each ground cumin and ground coriander; 2 red onions , halved and cut into thin wedges; 2 skinless chicken breasts , cut into bite-sized chunks; 1 small butternut squash , cut into 1cm chunks (no need to peel); x cans tomatoes; zest and juice 2 lemons; 200g cherry tomato , halved; 140g couscous; small bunch coriander , roughly chopped