In nonstick saucepan, heat oil over medium-high heat. Sprinkle chicken with salt and pepper. Add to oil and cook until browned all over, 4 to 6 minutes per side. Remove and keep warm.
In same skillet, cook onion and bell pepper over medium heat until tender. Add rice, broth, saffron and bring to boil. Add chicken, cover, reduce to a simmer and cook until rice is tender, about 30 minutes.
Add peas and pimientos and let stand, covered, a few minutes before serving.