In a large saucepan cook wax or green beans in a small amount of boiling salted water for 15 minutes. Add asparagus and broccoli. Cook for 5 to 10 minutes more or until vegetables are crisp-tender. Drain; keep warm while preparing sauce.
Meanwhile, cook pasta according to package directions. Drain; keep warm while preparing sauce.
For sauce, in a medium saucepan cook red or green sweet pepper and green onions in margarine or butter until tender but not brown. Stir in chicken broth and nutmeg. Bring to boiling; reduce heat. Stir together yogurt and flour. Add yogurt mixture to saucepan. Cook and stir until thickened and bubbly. Stir in Parmesan cheese. Cook and stir for 1 minute more or until the sauce is smooth. Pour sauce over cooked vegetables; toss gently to coat.
Arrange pasta on individual plates or a large platter. Spoon the sauce over the pasta. Sprinkle with pine nuts or slivered almonds. Makes 4 main-dish servings.