1. In a large skillet, over medium-to-high heat add some oil and the chicken breasts, season with salt & pepper. Fry until starting to brown and about 90% cooked through. Add the fresh oregano for the last few minutes of frying. Remove the chicken from the pan temporarily.
2. Add a bit more oil and fry the pepper, celery & onions until they begin to soften.
3. Add the tomatoes, garlic and a bit of salt & pepper. Fry until the tomatoes start to soften ~1-2 minutes.
4. Add the chicken back to the pan along with the remaining ingredients, except for the toppings. Mix well, cover, and reduce heat to just a simmer until the orzo is cooked, around 6-8 minutes.
5. Add the toppings to the individual plate & enjoy!