Mexican chicken stew

Name: Mexican chicken stew
Prep time: 20 min
Cook time: 25 min
Total time: 45 min
Cuisine: Mexican
Ingredients: 1 tbsp vegetable oil; 1 medium onion finely chopped; 3 garlic cloves finely chopped; ½ tsp dark brown sugar; 1 tsp chipotle paste (we used Discovery); 400g can chopped tomatoes; 4 skinless, boneless chicken breasts; 1 small red onion sliced into rings; a few coriander leaves; corn tortillas or rice to serve