Heat walnuts in a dry skillet over medium-high heat 1-2 minutes until walnuts are slightly toasted. Set aside and reserve. Coat a 12-inch nonstick skillet with vegetable cooking spray and set over medium-high heat. Add onion and saute, stirring occasionally, 3 minutes. Reduce heat to medium and add pumpkin, 2 tbs of the concentrate, 1 tbs of the Sage and 6 tbs of the walnuts; stir and heat through. Season with salt and pepper. Set aside; keep warm.
Cook lasagna noodles according to package directions; drain well. Cut each noddle into 3 equal-sized rectangles. Set aside; keep warm. To make the sauce, in a small saucepan over medium heat combine broth, chard and the remaining 2 tbs concentrate and 1 tbs Sage. Set aside; keep warm.
To assemble ravioli, for each serving place 3 noodle pieces on a dinner plate; top each with 2 1/2 tablespoons of the pumpkin mixture. Cover each with another noodle piece. Drizzle with sauce and sprinkle with the remaining 2 tablespoons walnuts, dividing equally.