Into a medium-size pot over medium-high heat, add the olive oil. When the oil is hot, add the onion. Cook for 3 minutes, stirring frequently until softened. Add the rice and stir to coat. Continue cooking for an additional 1 minute.

Pour in the green enchilada sauce, water, and green chiles.

Bring to a boil then reduce the heat to low. Cover and simmer for 20 minutes, until rice is cooked. Let the rice stand for 5 minutes then fluff with a fork and serve.