In a large sauté pan, heat 1 tablespoon of olive oil over medium high heat.
Add the chicken to the pan and let it cook for 10 minutes until the chicken is brown on the exterior. Make sure to stir occasionally to brown all sides.
Note: If there is some excess liquid released while the chicken cooks, remove some of the liquid by placing a few paper towels in the bottom of the pan and discarding. Removing some of the liquid will allow for a nice golden brown exterior on the chicken.
While the chicken is cooking, chop the onions and garlic.
Once the chicken has browned, remove it from the pot and set aside in a bowl.
Reduce the heat to medium. Add onions and garlic to the pan and cook for 3 minutes or until soft and translucent. If you need to add a splash of oil to the bottom of the pan to prevent sticking, go for it!
Add the uncooked orzo to the pan. Stir for one minute to give the orzo a gentle toast.
Add the cooked chicken and chicken stock to the pan. Stir well.
Cover the pan and cook over medium low heat for 10 minutes, stirring every few minutes to make sure the orzo does not stick to the bottom.
After 10 minutes, the orzo should be fully cooked.
Once the orzo has cooked, stir in pesto until combined.