Preheat oven to 350 degrees. Spray 8" round baking dish with non-stick cooking spray.
In medium saucepan, bring 1 1/2 cups water to a boil and add rice. Reduce heat to low, simmer covered for 17 minutes, until rice is tender and all liquid absorbed. Remove from heat and set aside.
Cut off stem ends of bell peppers. Remove and discard seeds. In large pot of boiling water, cook peppers and stem ends 5 minutes, until softened. Transfer peppers and ends to paper towels, placed cut-side down to drain.
In a large non-stick skillet, heat oil, then add onions and garlic. Cook over medium-high heat, stirring frequently for 5 minutes, until onions are softened. Add chicken, salt, and black pepper; cook, stirring to break up meat for 4-5 minutes, until the meat's no longer pink. Add in crushed tomato, half the basil, and the cooked rice. Cook, stirring constantly, for three minutes until the mixture comes to a boil.
Spoon 1/4 of the chicken mixture into each drained bell pepper; top each with a stem end. Stand the ppepers upright in prepared baking dish, bake for 30 minutes.
Combine tomato sauce and the other half of the basil; spoon tomato sauce mixture over the baked peppers; bake an additional 10 minutes, until peppers are tender and the filling and sauce are heated through.