In a large saucepan, heat the oil over medium-high heat. Add the couscous and cook until lightly toasted, 2 to 3 minutes. Add the broth, lemon zest, lemon juice, salt and pepper. Bring to a boil. Reduce the heat to medium-low and simmer uncovered until the couscous is tender but still firm to the bite, about 8 minutes.
Stir in the cheese, green onions, peas and chicken. Spoon into bowls and serve.