Melt a knob of butter in a large pan, add the onion and garlic and cook until soft and translucent. Stir in the rice until coated with butter.
Add the wine and stir until evaporated. Add the stock a ladle at a time until the rice is cooked but still with a little bite (add the peas and chicken in the last 5 minutes of cooking to heat through). The rice should be creamy but firm to the bite.