Preheat oven to 350 degrees F. Spray a 9x13- inch baking dish with nonstick cooking spray; set aside. Cook pasta according to package directions; drain and set aside.
In a large mixing bowl, combine cooked pasta, chicken, ham, swiss cheese and parmesan cheese; set aside.
Melt butter in a large skillet over medium-high heat. Mix in flour and cook for an additional 1- 2 minutes. Gradually whisk in chicken broth and cook for 3 minutes, or until thickened. Remove from heat and mix in milk, yogurt, garlic powder, salt, lemon juice and dijon mustard until well combined.
Add pasta mixture to yogurt mixture, mix until combined and spread in an even layer in prepared pan.
In a small bowl, combine melted butter and breadcrumbs and sprinkle on top. Sprinkle Italian seasoning on top and bake, uncovered, for 30 minutes.