In a large skillet, heat 1 T oil over medium-high heat. Add zucchini and peppers and season with salt and pepper. Cook veggies until they have softened. Add chicken to the pan and cook until heated through. Turn heat to low until risotto is ready.
In a large saucepan, melt butter and oil over medium-high heat, saute onions and garlic until onion is translucent. Add in rice and cook for 1 minute until the rice has absorbed some of the liquid and has turned opaque.
Gradually add in chicken stock, 1 ladle at a time. Stirring until the liquid has been absorbed before adding another ladle.
Continue ladling stock and stirring until all of the broth has been incorporated and the rice is tender. Add chicken mixture and Parmesan into the pot.