In a small bowl, combine spices for chicken: 2 teaspoons oregano, 1 teaspoon paprika, coriander, salt, and pepper. Season both sides of chicken with spices and place on a plate. Squeeze lemon juice over chicken and allow to sit.
Heat 1 tablespoon olive oil in a Dutch oven or large, oven-safe pot When ready, in a 5-quart Dutch oven like this one or a large oven-safe pot over medium-high until shimmering. Add chicken and brown the chicken on both sides, about 3-4 minutes per side (do not cook through). Remove chicken to a plate and set aside.
In the same pot, add green bell pepper slices and cook for 3-4 minutes per side or until seated. Remove to a plate and set aside.
Add 1 tablespoon more of oil to the Dutch oven. Add chopped onion and bell peppers; cook for 5 minutes, stirring regularly, until soft. Add garlic, and cook another 30 seconds or until fragrant. Add plum tomatoes, artichokes, broth, remaining 1 teaspoon oregano and 1 teaspoon paprika, and black pepper, to taste. Bring to a boil and stir in orzo.
Nestle the chicken pieces into the mixture, and top with the green bell pepper slices. Transfer the pot to heated oven. Bake, uncovered, for 20 minutes. Remove from oven, cover and let sit 5 minutes undisturbed. Top with feta before serving.