1. Rinse chicken and pat dry. Combine oregano, chili powder, cumin, salt and pepper in a small bowl. Sprinkle half of spice mixture over chicken and rub in with fingers; set remaining aside.
2. Heat oil in a large nonstick skillet over moderately high heat until hot but not smoking. Add chicken and cook, turning, until browned on all sides, about 8 minutes. Transfer to a 6-quartslow cooker.
3. Place canned tomatoes, onion, garlic, chipotle and remaining spice mixture in a blender. Cover and blend until almost smooth; pour over chicken. Add broth.
4. Cover and cook, 4 to 5 hours on low or 2 to 2-1/2 hours on high. Gently stir in rice, cover and cook on high, stirring once, 30 minutes. Turn cooker off, stir in peas, cover and let stand 15 minutes.
5. Cut cherry tomatoes in half and toss with cilantro; serve over chicken and rice with lime wedges on the side.