Chinees fridge raid fried rice recipe

2 tbsp vegetable oil 1 white onion, finely chopped 1 carrot, finely chopped 100g green beans, chopped 1 red or yellow pepper, finely chopped ½ medium broccoli, chopped into small florets 150g cooked chicken (or any other meat), roughly chopped 300g cold cooked rice 2 eggs, beaten 1 tbsp sesame oil 1 tbsp oyster sauce 1 spring onion, finely sliced 1 tsp toasted sesame seeds