In large nonstick skillet, heat oil over medium-high heat and cook onion, stirring occasionally, 2 minutes.
TIP: To create this recipe with lower sodium, use a reduced-sodium prepared rice mix. Specialty rice such as popcorn or pecan rice can also be substituted.
Meanwhile, remove seasoning packet from rice mix and set aside. Add rice mix to skillet and cook, stirring constantly, 2 minutes. Add seasoning packet, tomatoes and water according to package instructions; bring to a boil. Reduce heat to low; cover and simmer 15 minutes.
Stir in chicken and peas. Increase heat to medium; cover and cook until heated through, about 3 minutes.