Season chicken, if desired, with salt and black pepper.
Melt margarine in large nonstick skillet over medium-high heat and cook chicken, stirring occasionally, until chicken is thoroughly cooked, about 4 minutes. Remove chicken and set aside.
Add mushrooms to skillet and cook over medium-high heat, stirring occasionally, until mushrooms are tender and liquid is almost evaporated, about 5 minutes.
Stir water, Knorr® Rice Sides™ - Creamy Chicken flavor, green beans and sugar snap peas into same skillet. Bring to a boil over high heat. Reduce heat to low and simmer covered 7 or until rice is tender. Remove from heat and stir in sour cream and chicken.