Cheesy chicken lasagna

Name: Cheesy chicken lasagna
Prep time: 15 min
Cook time: 1 h 30 min
Total time: 1 h 45 min
Cuisine: Italian
Ingredients: 500 g (1lb) ground chicken / chicken mince; 1 large onion (finely chopped); 2 celery spears (finely chopped (+- ½ cup)); 2 large carrots (finely chopped (+- 1 cup)); 250 g (½lb) mushrooms (finely chopped ); 4 garlic cloves (minced ); 1 tsp dried oregano; 1 tsp Italian herbs / Italian seasoning; ½ tsp chilli flakes; 1 cup chopped tomatoes ((I used cherry tomatoes that were starting to soften) ); 1 cup tomato puree ((passata / crushed tomatoes) ); 2 tsp tomato paste; 1 cup chicken stock; 1 tbsp Balsamic vinegar; 1 tsp sugar ((optional)); 2 cups bechamel sauce / cheese sauce ((my recipe is linked) ); 250 g (½lb) no-boil lasagna sheets; 1 cup grated cheddar cheese; 2 cups grated mozzarella cheese; ½ cup Parmesan cheese