Baked Grecian Chicken Salad

1/4 cup unsalted butter, melted
1 lemon, juiced
1/2 tsp. garlic powder
1-1/4 tsp. oregano
1-1/4 tsp. Greek herb seasoning
4 boneless skinless chicken breast halves
2 plum tomatoes\raw, diced
1 cucumber, peeled and sliced
1/2 green bell pepper\raw, cut into strips
1/4 purple onion\raw, sliced
2 Tbs. red wine vinegar
1 Tbs. olive oil
2 Tbs. vegetable oil
1/8 tsp. dried basil
1/8 tsp. sugar
1/8 tsp. dry mustard
1 package mixed Italian salad greens
2 ounces feta cheese, crumbled
1/4 cup black olives
1/4 cup bottled pepperoncini (salad peppers)

Preheat oven to 350°F. Combine butter, lemon juice and garlic powder in a bowl. Add 1 tsp. oregano, 1 tsp. Greek seasoning and salt and pepper to taste. Place chicken in baking dish. Pour butter mixture over chicken. Bake 45-50 minutes, basting occasionally, until chicken is just cooked through. Combine tomatoes and next 9 ingredients in a bowl. Add remaining oregano and Greek seasoning. Season with salt and pepper to taste and mix thoroughly. Place salad greens in a large bowl. Slice chicken into thin strips and arrange on top of salad. Top with tomato-cucumber salsa and sprinkle with feta cheese. Garnish with olives and pepperoncini pepper.