1. In a 6-8 quart pan, bring about 4 quarts of water to a boil over high heat; stir in orzo pasta and cook, uncovered until just tender to bite (10-12 minutes). Or cook according to package directions.
2. Meanwhile, drain sun-dried tomatoes, reserving 1 tbsp of the oil. Cut tomatoes into thin slivers and place in a large bowl with spinach and diced tomatoes. Add oregano, lemon juice, broth, cheese and chicken. Add the reserved tomato oil and toss to combine.
3. Drain pasta well and add to chicken mixture; toss to combine. Serve warm or cold.