spring vegetable lasagna

Cooking spray
8  cups  torn Swiss chard (about 3/4 pound)
2  cups  chopped yellow squash
1 1/2  cups  chopped onion
1  cup  sliced mushrooms
1/2  teaspoon salt
1  tablespoon butter
4  garlic cloves, crushed
2  tablespoons all-purpose flour
1 1/2  cups milk
1 teaspoon nutmeg
1/4  cup grated fresh Parmesan cheese
2  cups ricotta cheese
1/2  teaspoon dried oregano
1/4  cup  grated Asiago cheese
1/2  cup  grated Monterey Jack, cheese
6  no-boil lasagna noodles
Heat a Dutch oven coated with cooking spray over medium-high heat. Add chard, squash, onion, mushroom, and salt; sauté 10 minutes or until tender. (OR Preheat oven to 425°. Dice vegetables, drizzle with EVOO, salt and pepper and roast on two baking sheets for 30-45 minutes until caramelization begins. Prepare chard, add to heated vegetables.)
Melt butter in a saucepan over medium heat. Add garlic; sauté 30 seconds. Add flour, and cook 1 minute. Stir constantly with a whisk. Gradually add milk, nutmeg, stirring with a whisk until blended. Cook until thick (for about 4 minutes). Remove from heat; add Parmesan. Stir until cheese melts.
Preheat oven to 375°.
Combine ricotta, oregano, salt and pepper in a bowl.
Spread 2 tablespoons milk mixture in the bottom of an 8-inch square baking dish coated with cooking spray. Arrange 2 noodles over milk mixture; top with half of ricotta mixture, half of vegetable mixture, and 1/2 cup milk mixture. Repeat layers, ending with noodles.
Spread remaining milk mixture over noodles. Sprinkle with cheeses. 
Bake at 375° for 45 minutes. Let stand 15 minutes.