Cook pasta according to package directions, omitting salt and oil. Rinse with cold water; drain and set aside.
Stir together ricotta cheese and next 4 ingredients.
Coat an 11- x 7-inch baking dish with cooking spray, and pour 1/2 cup salsa in bottom of dish. Spoon cheese mixture evenly into shells, and arrange in dish. Pour remaining salsa over shells.
Bake at 350° for 20 minutes. Sprinkle with Monterey Jack cheese. Bake 10 more minutes or until thoroughly heated and cheese melts. Let stand 10 minutes before serving.
Note: For testing purposes only, we used D. L. Jardine's Holy Chipotle Salsa.
* 1 or 2 canned chipotle peppers in adobo stirred into 2 cups reglar mild salsa may be substituted for chipotle salsa. Canned Chipotle peppers may be found in the Mexica section of supermarket. Store remaining peppers in a zip-top plastic bag in refrigerator up to 2 weeks or in freezer up to 2 months.