Bring a large saucepan of water to the boil. Add the stock powder and risoni and cook according to packet instructions (about 8 minutes). Drain and run under cold water.
Marinate the chicken tenderloins in the olive oil and lemon pepper seasoning. Place a large frying pan over medium–high heat and cook the tenderloins for about 5 minutes each side (depending on size). Remove and set aside.
For the dressing: Mix together all the ingredients in a bowl or jug. Season and adjust to taste.
Place the risoni, cherry tomatoes, capsicum, cucumber, red onion, parsley, feta and pine nuts in a large bowl. Drizzle over the dressing, season well and toss the salad together. Arrange the chicken tenderloins on top and squeeze over some fresh lemon juice before serving.