Heat oven to 350°. Place chicken breasts in baking dish with 1/2” water to poach. Cook for 20 min or internal temp reaches 160°. Remove from oven & allow to cool. Cut into bite-size pieces & chill.
Meanwhile, bring 3 C water to boil and add orzo to cook. Reduce heat to medium and allow to cook until al dente (approx 5-7 min). Drain orzo thoroughly & transfer to large bowl to cool, occasionally tossing with a fork to aid cooling.
Chop feta into ½ “ square pieces & set aside. Zest & juice lemon. Dice chives & tear basil into small pieces.
Toss everything together, season with salt & pepper and serve.