Prepare rice or pasta according to package instructions.
Prepare vegetables: dice the onion and garlic; cut the red pepper, mushrooms, carrots, and zucchini into bite-sized pieces. Dice the chicken breasts.
Heat the olive oil in a large pan over medium-high heat. Add the chicken and cook for 5-7 minutes, turning occasionally, until browned on all sides.
Add the onion and garlic, cook for 1-2 minutes until fragrant.
Add the red pepper, mushrooms, and carrots, cook for 2-3 minutes.
Add the zucchini and a splash of water, cover the pan, reduce heat to low, and simmer for about 10 minutes until vegetables are tender and chicken is cooked through (internal temperature 74°C / 165°F).
Stir in the sour cream, Italian herbs, salt, and pepper until heated through.