In a bowl, combine salt, lemon pepper, garlic and onion powders, nutmeg, chili powder, and cayenne pepper. Place scallops in a bowl; sprinkle with spice mixture and toss to coat well. Cook the pasta in boiling salted water just until tender. Just before pasta is done, heat the oil and butter in a skillet. Saute the scallops, tossing to cook on all sides, until just done. Place scallops in serving bowl.
To the skillet, add the chicken broth and bring to a boil.
Stir cornstarch and water mixture into the pan to thicken the sauce; bring to a simmer. Add the scallops and sour cream to the skillet. Drain the cooked pasta and stir into hot scallops mixture.