Cook onions in olive oil. In large mixing bowl combine spinach, ricotta cheese, Parmesan cheese, garlic powder, oregano, nutmeg, and lemon juice. Stir in chicken and onions. Season to taste with salt and pepper.
Spray eight, 10-oz. custard cups with non-stick spray. Line each dish with an egg roll wrapper. Divide chicken mixture among the 8 dishes. Fold the ends of each wrapper over the top of the chicken mixture,sealing to make a bundle. Brush with melted butter. Bake in 350°F oven for 20-25 minutes or until tops are golden.
To serve, loosen bundles with a knife and and remove from cups.